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1. glas wall of box a 7 O ZJ sheet water lt lt pS sheet glas wall of box lens lens pinhole pinhole diode diode Figure 2 5 Top view of the path of the laser beams from front lens of the sending optics through the mea surement section glass walls and sheet towards the diode optics 3 A Yoo fl i en bA A z OO OO O O OT OT y y Z Pe 1 LL 2 view A A Figure 2 6 Traversing mechanism fi gure from Steenbergen 1995 view in the direction of the fbw top left side view top right and the rotatable plate to which the optics are mounted bottom 1 transmitting optics 2 photo detectors 3 rigid frame 4 frame standing on fbor x direction is fbw direction y is horizontal perpendicular to fbw direction z is vertical 2 2 4 Connections In figure 2 7 the connections between the different components of the LDA signal processing system are shown For the calibration of the frequency trackers the shifter and tracker are disconnected and the output of the function generator is connected to the photo detector input connectors of the trackers The connections between the components of the traversing system are shown in figure 2 8 Figure 2 9 shows the connections between the different components that are used for the measure ment of flow rate water temperature and pressure drop For the pressure drop measurement
2. de oe de oP do ae startparsam To initialize PARSAM for a given number of channels and given number of samples and to start sampling Strorage option selection offset binary data This is a modified version of the startparsam by Roger van Galen A IN number of channels a SEN IN number of samples Interface ge oe de oe PROCEDURE startparsam n_ integer parsam_fill_ array Procedure parsam fill array Purpose To fill an array of given length with data from a given number of channels in a given range Interface EL IN first channel number de IN last channel number n_ IN number of channels pardat IN array with pairs of ADC samples for all channels nsamp IN number of samples PROCEDURE parsam_fill_array f_ 1_ pardat n_ CONST integer REF ARRAY 0 0 OF integer nsamp CONST integer 3 2 10 STEPLIB Library steplib Purpose To provide routines for control of stepper motors for LDA system Author Most routines have been written by Wiendelt Steenbergen Modifications and new routines are due to Arnold Moene Date 1993 1995 Required libraries HWD st5 HWC GSD iolib GSC GSD ldadec GSC GSD ldalib GSC do_step Procedure do_step Purpose To do a certain number of steps in some direction with a cetrain stepper motor Interface mo IN motor number st IN number of steps IN direction 1 or 0 PROCEDURE do_step mo st dir nat2
3. sampl intdat i unsigned int samp0 lt lt 16 3 2 Exchange samples and swap bytes in sample nat2dat 2 i 1 unsigned short samp0 gt gt 8 unsigned short samp0 lt lt 8 nat2dat 2 i unsigned short sampl gt gt 8 unsigned short sampl lt lt 8 name type rer real ustar real re real t real q real yplus real nsamp int freq int cal real conv real travangreal ldaang real mp real pgain real os real range int shift int NNNN NRF BD BR RR RR Re eS Ht description radial position r R friction velocity u m s Gf pressure gradient measured as well Reynolds number Re water temperature C flow rate m2 hr distance from the wall in plus units total number of samples for this point sampling frequency Hz calibration factors for the 2 trackers elements 0 1 2 for tracker 1 2 x 2 matrix to convert velocities from phyisical frame to LDA frame traversing angle radians angle of LDA radians gains of amplifiers gains of PARSAM offsets of amplifiers range of tracker between 1 and 7 shift frequency Hz Table A 5 Data in group header in binary fi le 45 Bibliography Smeets R and Nijmweegen F v 1993 User manual PhyBUS PARSAM 25 250 Parallel Sampling ADC Physical and Technical Laboratory Automation Group Department of Physics University of Technology Eindhoven Einhoven first edition BL 92 02 Steenbergen W 1995 Turbulent pipe flo
4. get count Procedure get_ count Purpose To get the value of the position counter of one of the two moving devices vertical or horizontal Interface ch IN the number of the moving device 1 horizontal 2 vertical PROCEDURE get_count ch integer integer set_count ae Procedure set_count Purpose To set the value of the position counter of one of the two moving devices vertical or 5 horizontal Interface ch IN the number of the moving device 1 horizontal 2 vertical offs IN the value to set the counter to de Procedure Purpose move_y to move the measuring volume to a given y position ge de de The position is given in steppenmotor steps which 41 5 equal 0 02 mm Interface pos IN position in steps PROCEDURE move_y pos integer Procedure move_z Purpose to move the measuring volume to a given z position The position is given in stepper motor steps which equal 0 02 mm Interface pos IN position in steps PROCEDURE move_z po integer Procedure reset Purpose to move measuring volume to centre of pipe Interface none PROCEDURE reset Procedure to_rr Purpose moves the measuring volume to a position given in r R coordinates and for a given traversing angle Interface r_over_r IN position trav_angle IN traversing angle PROCEDURE to_rr r_over_r trav_ang CONST real switch_on Procedure Purpose To keep LDA at sa
5. PROCEDURE offset swa to int2 PROCEDURE gain swa g0 int2 getadc_char Procedure get_adc_char Purpose To get ADC characteristics volts per count and counts at zero voltage Interface parsam_adc IN is PARSAM ADC of which you want characteristics v_per_c OUT volts per count zero_c OUT counts at zero voltage PROCEDURE get_adc_char parsam_adc boolean v_per_c REF real zero_c REF nat2 3 2 3 CFGLIB Library cfglib Purpose Routines used for the configuration of the experiment Author Most routines have been written by Wiendelt Steenbergen Modifications and new routines are due to Arnold Moene Date 1993 1995 Required libraries HWD st5 HWC GSD mathlib GSC GSD iolib GSC GSD 1dadec GSC Note Library tested only for PEP030 2 30 0 Procedure set_raw_type Purpose To set raw_store_type to a value according to values of number of parameters Interface block_d IN one or more non continous blocks lock_d IN store lock data return value whether valid type has been set PROCEDURE set_raw_type block_d lock_d integer boolean get raw type Procedure get_raw_type Purpose To get from raw_store_type the values for a number of parameters Interface block_d OUT one or more non continous blocks store lock data whether valid values have been gotten lock_d OUT return value ge a de oP de ge oe de ol lock _d REF integer PROCEDURE get_
6. the program ensures that the calibration of the trackers is performed with the same settings of gain and offset for the amplifier as the actual measurements In the ADC and amplifier menu the option O lets one set the offset of the amplifier the offset is applied before the gain For rescaling of the tracker output to make it usable for the PARSAM useful combinations of gain and offset are 2 and 5V or 4 and 2 5V respectively Finally the PARSAM has a build in amplifier as well which can be set through option P 3 1 7 Positioning of the laser Option L in the main menu will produce the menu Positioning of the laser Besides the two options given here horizontal alignment option H and determination of the centre of the pipe option C the total alignment entails more steps e The glass walls of the measurement section need to be exactly vertical This is checked by placing a brass plate on top of the measurement section and a precision water level on top of the brass plate e The traversing system needs to be horizontally parallel to the pipe axis This is checked as follows Rotate the laser and its optics around the optical axis over 90 degrees so that the reference beams describe a vertical plane Let the reference beams illuminate the glass wall of the measurement section If the beams are perpendicular to the glass wall the beams and their reflections will lie in one plane For measurements where the
7. Sampling frequency now 100 Hz Quit to main menu u zZ Wd wot OPTIE Q 3 1 3 File and data menu The file and data menu offers the possibility to define which type of LDA data should be collected and where and how it should be stored It is accessed from the main menu through the option F and gives the following menu dd Menu level 2 File and data menu dd OPTIONS DV DL NVP NLP SLR SLP SVP Q OPTION SLR Raw data to LDN y n y change standard VAX device now gsd change standard LDN device now gud name processed data file on VAX now gsd mn076axx gsd name processed data file on LDN now gud mn076axx gsd Save raw data to LDN Save processed data to LDN Save processed data to VAX Quit to main menu The arrangement of a VAX device and a LDN Local Data Net device is based on the historical situation when most data and programs where stored on a VAX at the Technical Laboratory Au tomation Group and a fast link using LDN was used within the Fluid Dynamics Laboratory Nowa days still two separate systems exist but the VAX has been replaced by a PC at the Fluid Dynamics Laboratory and the disk space it uses resides at the a DEC Alpha tnl phys tue nl directory tnlu3 phylan fti No speed difference exists anymore between VAX and LDN The data written to LDN reside on tnl phys tue nl as well in the directory tnlu2 data The de vice that can be set with options DV and DL are the
8. connection via LDN Transfer to LDN 44943 820 byte s This is SLOWER than the nominal value 45000 000 Hit any key 28 The actual sampling frequency is checked against the one selected in the setup menu see 3 1 2 Then the block type of for raw data storage is checked if raw data storage has been selected in the file menu see 3 1 3 Finally the actual speed of the LDN connection is checked against the nominal value given in the file menu if raw data storage has been selected After all tests have been passed the following menu appears Ha EH aE EH aE EH FE HE AE EH HE AE a FE E FE AE a EH FEAE EH aE HE FE E EH E AE AE EH EER AAA Menu level 2 Measurements menu dd OPTIONS S Start automatic measurements M Start manual measurements X Max multiple of required samples to get now 2 0 L Lock limit now 2200 P Set position pointer to specific value now 3 R Set current index in results table now 44 F Flag point 0 0000000 as done D Toggle display of Re temp and flow now OFF Q Stop OPTION M Option S starts the automatic LDA measurements In the case of processed data storage this implies the following steps e The program moves the optics to the radial position given in the position table starting at the array index given after option P e The program determines the quality of the signal A limited number of samples is taken If for less than 75 sfrac in the progra
9. layer mean velocities with large turbulent fluctuations including backflow The tracker menu is shown below dd Menu level 2 Trackers dd OPTIONS R1 Set range tracker 1 now 5 calib date 26 3 1998 8 45 43 R2 Set range tracker 2 now 5 calib date 26 3 1998 8 45 43 Set shift frequency for tracker 1 now 20000 Set shift frequency for tracker 2 now 20000 Calibrate trackers Delete all calibrations Stop a II uot OPTIE RI Give range index of tracker 1 5 The pre shift frequency can be choosen for each channel separatly as well Possible values com prise fs A x B x CkHz where A 1 or 1 B is any integer value between 1 and 9 and C is either 10 100 or 1000 dd Menu level 2 Trackers dd OPTIONS R1 Set range tracker 1 now 5 calib date 26 3 1998 8 45 43 R2 Set range tracker 2 now 5 calib date 26 3 1998 8 45 43 Set shift frequency for tracker 1 now 20000 Set shift frequency for tracker 2 now 20000 Calibrate trackers Delete all calibrations Stop sl S2 iE D Q OPTIE S2 Give shift for tracker 2 in Hz 20000 21 Calibration of the trackers can be done with option C which will yield the following menu HRT Ha EH FE FE HE AE FE HEH E AE FE FE E FE FE FE EE Ha EH aE Ha EH AEH EH RAT HRT HRA EH HH REE Menu level 3 Calibration Ha E AE AE FEAE FE FE FEAE AE FE HE AE FE FE HE AE FE FE E AE FE FE E FE FE FEE AE FE FE AE FE FE HE AE FE FE FE F
10. maximum number of samples in from PARSAM length of array is 0 max_intsamp integer Current maximum number of samples max_nat2samp integer max_nat2locksamp integer if Nominal speed of LDN connection in nom_ldnspeed real Way in which raw data are stored an raw_store_type integer Number of signals n_signal integer Experiment code expcode ARRAY 0 7 OF char Current menu level menu_level nati Current range number for both tracke rangeindex ARRAY 0 2 OF nat1 Current frequency shift on preshifte f_s ARRAY 1 2 OF integer Maximum frequency in tracker range def_range ARRAY 1 7 OF integer max Nominal gains of amplifiers used wit mp_nom ARRAY 8 OF real Table with real gains of amplifiers mp_table ARRAY 1 2 8 OF real Conversion matrix freq gt speeds scf ARRAY 1 2 1 2 OF real Calibration 2nd order coeff ARRAY 42 OF real of trackers Transformation matrix from discrete tion d downstream m H20 ig dp c dp dp integer array 5 max_intsamp nat2 array bytes sec d which rs 7 ranges freq h old ADC used with old ADC stepper motor index 1 and 2 tracker calibrated for range in tracker range nominal gain factors for amplifiers 32 coordinates to continuous pipe coordinates trmatr invtrmatr ARRAY 1 2 1 2 OF real and v v Array with processed data of each radial point res_table AR
11. name GSD SETUP GSD For the measurement mode option O one can choose between LDA measurements or pressure measurements 17 dd Menu level 3 Measurement mode dd OPTIONS 1 2 Q OPTION 1 lda pressure Exit The code of the experiment option C is used to generate the file name for the data file and is also stored in the binary file used to store raw data Sampling characteristics can be set with option F sampling frequency and N number of samples Please note that the sampling frequency is only used by the program to do some checks The program can not set it since the sampling frequency is selected by choosing the correct output of the pulse generator the PARSAM is triggered externally One can choose between two lenses with different focal lengths 80mm and 160mm This infor mation is used by the program to convert the Doppler frequency to velocities the beam geometry is different for the different lenses Furthermore two angles can be set The angle of the LDA option A is the angle of the LDA optics relative to the horizontal where a positive angle corresponds to an anti clockwise rotation when looking in the flow direction The traverse angle option T is the angle between the line through all positions to be measured and the horizontal same sign convention as for the other angle Usually one uses zero for this angle a horizontal traverse One could use 90 to make a direct measurement of the rad
12. o o 15 Connections for sensors measuring flow rate water temperature and pressure difference 15 Configuration for calibration of pressure transducers o o o 24 1 Introduction This report describes the hardware and software of the pipe flow system of the Fluid Dynamics Labo ratory at Eindhoven University of Technology It is not meant to be exhaustive it should rather serve as a collection of practical knowledge about the setup For scientific details about the flow system and the Laser Doppler Anemometry system the reader is referred to the thesis of Steenbergen 1995 The pipe system was originally designed for the study of the decay of swirling pipe flow Later on it has been adapted to study the combined effect of swirl and axial strain The water flow in the pipe system is driven by the pressure difference between the constant head tank on the roof about 10 meters above the actual measurement pipe and the basin in the basement about 4 meters below The horizontal pipe in which measurements can be made has a total length of 21m The flows that can be studied vary in two aspects In the first place the flows can either be swirling flows or not A guide vane swirl generator is mounted at the inlet of the horizontal pipe and can be configured in different ways as to generate flows with different shapes of the tangential velocity profile concentrated vortex wall jet and different swirl numbers up to about 0 8 Seco
13. oe de d PROCEDURE press _grad calib_press trans os Procedure calib_press_trans Purpose To enable user to calibrate a pressure transducer The user is prompted apply three pressure differences to the transducer as well as to do one measurement with open shunt valve to determine voltage at zero pressure difference A second order polynomial is fitted to the difference measurements and the coefficients are corrected for the open shunt voltage Calibration coefficients are based on pressure in Pa Method de de de dP de de de de dP de de de oP oP PROCEDURE calib_press_trans transd 3 2 5 FLOWLIB Library flowlib Purpose To provide procedures that have to do with the measurement with parameters of the process like temperature and flow rate Required libraries gsd iolib gsc hwd st7 hwc gsd adclib gsc de de de de de dP de de de init fbwtemp Procedure init flowtemp Purpose To get a first guess for values of fw end t_end dp_vao_end or to reset the values to bypass moving average Revision 28 05 96 arrays a_dp etc filled in one shot ge de de de de de PROCEDURE init_flowtemp rocedure urpose fw_end to return the average flow_rate mu computed from a_flow rocedure t_end urpose to return the average temperature mu from a_temp Procedure dp_vao_end Purpose to return the average pressure drop voltage from a_dp PROCEDURE dp_vao_end real Process flowtemp Purpose T
14. pipe has filled completely one should swiftly fill the entire chamber and make sure that no air is entrapped air can be removed with a syringe to which a small tube is attached To let the air escape more easily the measurement section should be installed slightly inclined during the filling operation the air bubbles will rise to one opening at the top of the chambers Once the water has reached the level of valve V3 and will flow out of the tap just below V3 which was left open to let air escape the tap near the desalination unit needs to be closed Then close the tap below valve V3 and open valve V3 slowly Some stretch of vertical tube needs to be filled with water so in order to prevent large pressure peaks in the pipe system valve V3 should be opened very carefully After filling has been completed the system should run for some time in order to smooth out differences in temperature and composition between the old and the new water Since during the cycle of emptying and filling of the system water which contains seeding material 1s lost to the sewer from time to time new seeding needs to be added to the water 2 1 4 Operation of the flow system In order to make measurements the water should flow through the pipe system Usually one needs to study a given flow at a given Reynolds number This Reynolds number is attained in the following way e Switch on the pumps e Open valve V3 e Open valve V4 e Open valve V1 e Open
15. system A N Phybus Figure 2 8 Connections for the traversing system pressure pressure flowmeter thermal transducer DP15 transducer DP45 SC 80 AS diode etn and DPI5 TI temperature DPI5 displ or isplay nee out BNC cable other cable location where to disconnect when disassembling the Phybus system Figure 2 9 Connections for sensors measuring fbw rate water temperature and pressure difference The resistor of 470 is used to convert the current output of the fbw meter to a voltage output 15 3 Software 3 1 Menu system The programs to control the LDA setup have been united under one menu system In order to use the menu system one needs to make use of a new PEP version newer or equal to PEPO30 2 30 0 Furthermore it is assumed that a VT240 terminal emulator is used 3 1 1 Starting the menu system Wait to get the MPS030 gt prompt Then load the PEP system QL MPS PEPO30TL Q and after completion RUN Then you are asked for the user ID User id and answer with GS unless you have been given another ID The next step is to load the monitor program MON HWD ZELPAGE HWC Finally you can automatically load all required libraries using the command load_1ibs which asks you for a filename from which the library names should be read give a carriage return to load the default file GSD lol ibs GSX or type an alternative name When you use the default the foll
16. tem described in the previous section The sub routines and functions provided by these libraries are described in the following sections 3 2 1 LDADEC The library LDADEC is loaded before all other libraries that where designed specifically for the pipe flow system LDADEC provides all global variables for those libraries and for the menu sys tem that is loaded on top of the libraries The documentation of each library mentions whether 1t needs LDADEC to be loaded or not se Library Purpose ae de To declare and partly initialize all global variables used by the LDA system Required libraries GSD iolib GSC Required compiled code none ge oe de de se Note Library test only for PEP030 2 30 0 Revisions 13 06 95 storage of raw data on VAX has been disabled in other libraries but relevant variables still present in LDADEC 13 06 95 defines for types of raw data storage replace store_at_once and contig_block DECLARE length of array with processed data len_data 20 dummy value no_value 999 address of ADC for LDA measurements adc_lda 1040 address of ADC for flow and temperature measurement adc_flow 1024 count value above which lock output should be for tracker to be locked lock_limit nat2 de te measurement mode measmode integer modecode ARRAY 3 8 OF char defines for type of storage of raw data raw_store_type old_adc_lock 0 con_1_lock 1 con_n_lock 2 no
17. 1999 Secondly the software used to control the measurements is described in some detail chapter 3 The latter chapter also gives information on the procedures used in the operation of the flow system alignment calibration etc For more information the reader is referred to For further questions e Wiendelt Steenbergen W Steenbergen tn utwente nl knows nearly all e Gerald Oerlemans pipe system mechanics e Jan Voskamp PEP system electronics history e Pim Sluijter optics e Gerard Trines PEP system electronics e Arnold Moene afmoene hp1 met wau nl present author 2 Hardware In this chapter the hardware of the pipe flow system is described the actual flow system section 2 1 the electronics and its connections section 2 2 2 1 Flow system For more details on the pipe system the reader is referred to Steenbergen 1995 2 1 1 Generation of flow The pipe system is shown schematically in figure 2 1 The pumps are used to keep the water level in the upper tank constant within about 5cm The flow rate is primarily controlled by operation of valve 2 the use of a submerged valve proved to be advantageous with respect to cavitation Valve 1 is used only occasionally for fine tuning of the flow rate In the given configuration the maximum attainable flow rate is of the order of 60 m hr which corresponds to a bulk velocity of 4 3ms for a pipe with inner diameter 70mm Four pumps are available to p
18. 4 5 18 sl Set shift frequency for tracker 1 now 20000 S2 Set shift frequency for tracker 2 now 20000 c Calibrate trackers D Delete all calibrations Q Stop OPTIE D 3 1 5 Pressure transducers Option D in the main menu makes one enter the pressure transducer sub menu FEAE HE AEAEE E AE FE HE AE FE FE HE AE FE FE HE AE FE FE E AE FE FE E AE FE FE AE AE FE FE E FE FE FEAE FE FE FEAE FE FE E FE AE E E AE FE E E AE FE E AE AEE AE AE AE E AE AE AE E AE FE E AE AE FEE EEEE Menu level 2 Pressure transducers dd OPTIONS T Set transducer to be used now none Calibrate transducer D Delete all calibrations P1 Position of first pressure point now 0 000 m P2 Position of second pressure point now 0 000 m R Set index in result array now 0 22 Q Stop OPTIE T 1 DP15 2 DP45 Give number of transducer 1 One can choose option T between two transducers DP15 and DP45 which have a range of Ap lt 880 and 35mm H20 respectively In order to calibrate the transducer select option C dd Menu level 3 Calibration dd OPTIONS O Set other than default transducer default DP15 current DP15 Calibrate pressure transducer Stop Cc Q OPTIE C Here you can choose to calibrate another transducer than the one currently selected for measurements option O or to proceed with the calibration An example with fake numbers of a calibration is given below dd Menu l
19. E FE E E AE AE E AE FE AE E AE AE AE AE AE FEAE AE AE AE E E E E EE EE E EEE EEE OPTIONS R Set other than default range default 5 current 5 e Calibrate trackers Q Stop OPTIE C Option R gives the opportunity to calibrate aan other range than the default one Option C starts the actual calibration The program asks to offer three different frequencies to the trackers This is done by connecting the output of the function generator to the photo detector input of the tracker An amplitude of the signal of 0 01 V is sufficient A useful setting of the trigger frequency for the PARSAM is 1000 Hz The frequencies to be applied depend on the seletced range of the tracker and the settings of the gain and amplitude of the amplifiers dd Menu level 4 Calibration of tracker dd Offer to tracker a frequency of 100000 Hz Hit any key Vl 1 0600375 V2 1 0386424 dvl 6 0037494e 02 dv2 3 8642406e 02 Offer to tracker a frequency of 250000 Hz Hit any key Vl 2 6264081 V2 2 5793993 dvl 12640810 dv2 7 9399347e 02 Offer to tracker a frequency of 450000 Hz Hit any key Vl 4 6954336 v2 4 6109991 dV1 19543362 dv2 11099911 Hit any key Finally option D in the tracker menu can be used to delete all calibrations dd Menu level 2 Trackers dd OPTIONS R1 Set range tracker 1 now 5 calib date 20 7 1998 14 5 18 R2 Set range tracker 2 now 5 calib date 20 7 1998 1
20. FERE E AE AE HH AE FE FEAE AE FE HE AE FE HEH HEE Ha EH Ha EH aE Ha EH aA EH EH RAT AE AE E E E HRA EH RE RRR Menu level 1 Main menu dd OPTIONS Setup of experiment Files Trackers calibration ranges etc Pressure transducer settings ADC Lining of LDA Preparation of measurements Measurements Control of steppen motors Open a monitor session Stop OPTION S In the following sections we will discuss the contents of each of the sub menus When you just have started the menu system the usual first step is to go to the Experiment setup menu in order to define the experiment or to retrieve the setup from a file 3 1 2 Experimental setup The layout of this menu is shown below dd Menu level 2 Experiment setup dd OPTIONS O Measure mode now lda Cc Code for experiment now mn076axx SN New name for setup file now gsd setup gsd Save setup to gsd setup gsd Retrieve setup from gsd setup gsd N Number of samples now 50000 F Sampling frequency now 100 Hz L Choose focal length of lens now 160 mm A Choose angle of LDA now 0 00 deg T Choose angle for traverse now 0 00 deg P Change table with positions measuring volume M Measure pressure gradient now OFF Q Quit to main menu OPTIE O When the current experiment does not differ too much from the previous one usually starts with retrieval of the setup from a file of which the name can be set by the command SN default
21. RAY 1 128 len_data OF real Names of variables in res table res_name ARRAY len_data 8 OF char Number of points in position table npoint pos_table Number of current observation in result table res_pt res_table Index in pos_table of current point pt integer Current point in pressure results array presspoint integer Table of radial positions r R where measurements will be done table whether processing was succesful pos_table ARRAY 1 128 OF real pos_success ARRAY 1 128 OF boolean Current amplifier offsets and gains os ARRAY 0 2 OF real mp ARRAY 0 2 OF real per channel PARSAM gain p_gain ARRAY 0 2 OF real Current y and z position in stepper motor coordinates _pos z_pos int2 ke Should when processing data 3rd moments be calculated do_3mom boolean Leave ldadec bewaren and loose values of global variables boolean Current value of focal length of lens flens real Angle of LDA lda_angle real relative to horizontal Angle of traverse relative to horizontal trav_angle Angle between reference beams beam_angle Current value of pipe radius radius real Answer to question answer boolean BEGIN 1 Define ranges FOR i IN 1 7 DO calib i false OD def_range 1 10000 def_rangel 2 33000 def_range 3 100000 def_range 4 333000 def_range 5 1000000 def_range 6 3300000 def_range 7 10000000 2 Set
22. ROCEDURE check_fname x CONST nat2 name REF string ce vax_ldn CONST nat2 boolean make_fname Procedure make_fname Purpose create a valid PEP file name from the user ID the file type a character and the actual name Interface uid IN user ID 5 name IN file name between and 5 type IN last character of extension device IN device name 5 vax_ldn IN VAX 0 or LDN 1 fname OUT constructed name PROCEDURE make fname uid CONST ARRAY 2 OF char CONST ARRAY 8 OF char CONST char device CONST ARRAY 3 OF char vax_ldn CONST nat2 fname REF ARRAY 16 OF char name type inq_fname Procedure ing fname Purpose To ask for a file name and check whether it is a valid EPEP file name Interface x Y IN coordinates for question text IN question 5 name OUT file name 5 valid OUT a valid name vax_ldn IN VAX 0 or LDN 1 PROCEDURE nat2 name REF string text CONST string valid REF boolean vax_ldn CONST nat2 fillname_array Procedure fill_name_array Pupose To fill an element in an array of strings This is a way to circumvent the fact that assignments to strings do not work Interface t IN string to write to array curr IN place in array to write arr IN OUT array to write to PROCEDURE fill na curr arri integer ARRAY 0 0 OF char 3 2 7 LDALIB Library ldalib Purpose Contains procedure related to LDA measurements and flow temperatu
23. Technische UniversiteiEtadhoven Eindhoven University of Technology address Den Dolech 2 P O Box 513 5600 MB Eindhoven The Netherlands Telephone 31 0 40 247 31 10 Telefax 31 0 40 246 41 51 Faculteit Technische Natuurkunde Werkverband Transportfysica Titel sl Experimental setup for measurements in turbulent pipe flow hardware and software Auteur A F Moene Verslagnummer R 1467 P Datum July 1999 Contents 1 Introduction 4 2 Hardware 6 ZL CBIOWSYSIEM er tn oe enen ee alek randen Beta hee eran et Ar datde a be 6 2 1 1 Generation of flow e o cs e eccna edoae ma a a e ee ee 6 21 2 Pipe SECHONS i ora Ts aud oen iet nf e Ml ld di oh BE dd Te 6 21 3 Filling and emptying the system e 6 2 1 4 Operation of the flow system o o e 9 2 2 Measurement hardware ee 10 2 2 1 Laser Doppler Signal processing ee 10 2 2 2 Traversidg system aten ptn mee attente Dara aide Bd a de 11 2 2 3 Miscellaneous measurements ee 11 224 Connections lt a fog Pe aren an acter Pe eed ee oe Re 13 3 Software 16 Sal Menu sy Ste at so wit emd ie hd gtd Aue dein bondi dee td bog ated 16 3 1 1 Starting the menusystem 2 000000 00004 16 3 1 2 Experimental SetUp e 17 3 1 3 Fileanddatamenu 0 0 0 0 000022 ee eee 19 34 TRACK EDS ie E ee AE a Me ai Ag nid A ae 20 3 1 5 Pressure transducers eee 22 3 1 6 ADC and amplifier men
24. adcopepn GUO Library tested only for PEP030 2 30 0 de de de de de de dP de de de meet adc_old3 meet adc_old2 meet _adc_old1 Procedures meet _adc_old3 2 and orl Purpose To get 3 2 or 1 arrays of nat2 from an ADC Interface ar b E IN OUT arrays to store data address IN start PHYBUS address of ADC num_chan IN number of channels to sample Note The number of samples to get is determined from the size of a b or c PROCEDURE meet_adc_old3 a b c ARRAY 0 OF nat2 address num chan nat2 AT adc_code 0 PROCEDURE meet_adc_old2 a b ARRAY 0 OF nat2 address num chan nat2 AT adc_code 0 PROCEDURE meet_adc_oldl a ARRAY 0 OF nat2 address num chan nat2 AT adc_code 0 33 adc_meas Procedures adc_meas Purpose To get a samples from a given channel of an ADC on a given PHYBUS address Interface address IN start PHYBUS address of ADC chan IN channel to sample return value nat2 samples from requested channel PROCEDURE adc_meas address nat2 nat2 nat2 Procedure loop_adc Purpose To continuously get samples from a number of channels Interface addr IN addres of adc nchan IN number of channels always starting at the first PROCEDURE loop_adc addr nat2 nchan nat2 offset gain Procedures offset and gain Purpose To set offset and gain of amplifiers Interface swa IN number of channel later converted to amp addres of amplifier amp gO IN gain to IN offset
25. amplifier gains 2 1 Real gains mp_table 1 0 1 00 mp_table 1 1 1 98 mp_table 1 2 3 95 mp_table 1 3 5 94 mp_table 1 4 7 89 mp_table 1 5 9 85 mp_table 1 6 14 89 mp_table 1 7 19 78 mp_table 2 0 1 00 mp_table 2 1 1 99 mp_table 2 2 3 96 mp_table 2 3 5 95 mp_table 2 4 7 92 mp_table 2 5 9 89 mp_table 2 6 14 97 mp_table 2 7 19 88 2 2 Nominal values mp_nom 0 3 Set defaults 3 1 Parsam is ADC parsam_in_use true mp 1 mp_tablel l mp 2 mp_table 2 os 1 0 os 2 O set_amp_offset p_gain 1 1 p_gain 2 1 set_pars_gain n_signal lock_limit 01 01 7 false set_amp_gain false false 2200 3 2 Set name of default setup file strcpy gsd setup gsd setup_fname set_setup_name true 3 3 Initially not OK to measure check first measure_ok false 3 4 Do not compute 3rd moments do_3mom false 3 5 Initialize PHYBUS init_pb 3 6 Set mode measmode 1 modecode 1 lda ia modecode 2 pressure 4 Give way to other libraries bewaren true WHILE bewaren DO monitor cls ing bool 20 20 Do you want to leave LDADEC and loose data r answer IF answer THEN bewaren ELSE bewaren true FI cls OD END false 3 2 2 ADCLIB Library adclib Purpose Contains routines for old ADC s Author Arnold Moene this library others ADC procedures Required libraries none Required compiled code GUD
26. an to read PROCEDURE readbool f file b REF boolean writebool Procedure writebool Purpose writes a boolean to a file as 0 or 1 Interface f OUT file to write to 5 b IN boolean to write Procedure ifwrite Purpose To write a string toa file only if a 5 boolean is true Method if boolean is true write 1 to file followed by the string Else only write 0 The counterpart of this procedure is ifread Interface b IN boolean IN OUT file to write to s IN string to write PROCEDURE ifwrite b ifread Procedure ifread Purpose To conditionally read a string Method a boolean is read from file either 1 or 0 If the boolean is true the string is read The counterpart of this procedure is ifwrite Interface b OUT boolean to read 5 IN file to read from s OUT string to read PROCEDURE ifread b REF boolean f file s REF string check_dev de Procedure check_dev Purpose checks whether a given device is a valid devi Interface dev IN device name vax_ldn IN VAX 0 ot LDN 1 PROCEDURE check_dev dev CONST string vax_ldn CONST nat2 boolean check_fname ae vax_ldn IN vax 0 OR ldn 1 Procedure check_fname Purpose To check whether this string is a valid EPEP filename i e with a valid device name and valid extension Interface x Y IN screen coordinates for error messages no message if x y 0 name IN proposed file name P
27. array index in the result array where the next measurement will be stored can be set dd Menu level 2 Pressure transducers dd OPTIONS T Set transducer to be used now DP15 calib date 3 6 1998 Calibrate transducer Delete all calibrations Pl Position of first pressure point now 0 000 m P2 Position of second pressure point now 0 000 m R Set index in result array now 0 Q Stop OPTIE R Give new index in results array 1 23 fixed bottle shunt valve pressure transducer Figure 3 1 Confi guration for calibration of pressure transducers sliding bottle If the measurement mode is set to pressure measurements in the setup menu see 3 1 2 the pressure transducer menu looks like dd Menu level 2 Pressure transducers dd OPTIONS T Set transducer to be used now DP15 calib date 3 6 1998 Calibrate transducer Delete all calibrations D Pl Position of first pressure point now 0 000 m Position of second pressure point now 0 000 m Set index in results table now 44 Do measurement Show results Stop oOngxz wt N OPTIE Q Extra options are M to actually do a pressure measurement with these settings and S to show the results Thus the procedure to do pressure measurements is e Calibrate the transducer to be used tubes e Set the axial positions of the taps used with options P1 and P2 e Do the measurement opti
28. be inaccurate The data for each radial position is described by a so called group descriptor This sequence is written just before the data of a given radial position thus all group descriptors are scattered through the file If dat at ype equals con_n nolock con n nolock nocon n lock ornoconn nolock the group descriptor starts with the integer PEP type nat 2 named tot cnt which is the number of blocks in which the data has been written In the other cases totent equals one by definition The rest of the group descriptor contains the data given in table A 5 Then it is finally time to actually read the data If the storage type is a multi block type con nnolock con_n_nolock nocon_n_lock or nocon_n_nolock the data are preceded by the number of the block stored as a nat 2 and the number of samples in the block an int stored as two nat 2 vari ables Then the blocks of actual data are stored for the storage types without lock information these are two arrays of integer data integers since that is the way it had been stored in the PARSAM memory For the storage types with lock information four arrays of data are present The integer data arrays have to be split since what was stored and read as an array of integers in fact contained data of type nat 2 or unsigned shorts in C Teh data are split as follows from a C program 3 1 Get two samples samp0 unsigned short intdat i gt gt 16 unsigned short
29. channel number RETURN gain of channel nr_ PROCEDURE w_pars_gain nr integer integer Procedure ena Purpose To start sampling by PARSAM disa To stop sampling by PARSAM rocedure urpose Ear tay PROCEDURE disa p status p_s Procedure tatus Purpose To write contents of certain Phybys registers used by the PARSAM see see PARSAM manual p 11 gt Note register contents is written in binary 5 form as well as in decimal form Interface n IN number of register relative to PARSAM base address PROCEDURE p_status n integer Procedure clearmem Purpose To clear specified memory i e give free to overwrite Interface n IN number of memory 0 or 1 PROCEDURE clearmem n integer Procedure n_chan Purpose To tell PARSAM how many channels have to be used during sampling Interface n IN number of channels PROCEDURE n_chan n integer Procedure init Purpose To initialize PARSAM for use with a specified number of channels Interface n_ IN number of channels PROCEDURE init n_ integer Procedure maxsamp Purpose To set maximum number of samples to be collected per channel de oe de oe PROCEDURE maxsamp i_ integer Procedure cro Purpose To set the number of the channel to be read out next to a specific value Interface n_ IN number of the channel of which EN o SOs Procedure Purpose Interface ge dP de de de dP dP dP oP
30. con_n_lock 3 old_adc_nolock 50 con_l_nolock 51 con_n_nolock 52 nocon_n_nolock 53 store_lock 0 nostore_lock 50 old ade 0 con_l 1 con_n 2 nocon_n 3 name of file for backup of setup temp_fname gsd tempfile gst maximum number of samples that can stored on VAX in one write statement put_array is limiting factor see boolean store_at_once vax_maxsample 2 16 ge oe de 31 Name of setup file setup_fname Name of file with radial positions postable_name Data file names ldnraw_name ldnproc_name vaxraw_name vaxproc_name ARRAY 16 OF char default device names on VAX and LDN vaxdev ldndev ARRAY 3 OF char Switches OK to measure i e measure_ok all checks OK PARSAM current ADC parsam_in_use Name of setup file set set_setup_name Name of position table file set set_postable_name Name of data files set set_vaxproc_name set_ldnproc_name set_vaxraw_name set_ldnraw_name Name of default devices set set_vaxdev_name set_ldndev_name Focal length of lens set set_lens Angle of LDA set set_angle_lda Angle of traverse set set_angle_trav Tracker range set set_track_range Shift frequency set set_track_offset ADC gains or offset set set_pars_gain set_amp_gain set_amp_offset set_rawvax set_procvax set_rawldn set_procldn Sampling freqency set set_freq Number of sampl
31. de de oP PROCEDURE sos i_ Procedure Purpose Note de oe oe oe PROCEDURE wacht initit se data should be read next PROCEDURE cro n_ integer sos To set the storage option select bits Valid values are 0 offset binary ADC data 10 to 9 9951 V 0 4095 1 2 complements ADC data 10 to 9 9951 V 2048 2047 2 add channel number to ADC data to 2 complements data in bits 15 12 3 same as O des IN storage option integer wacht To wait until PARSAM has one memory filled Value of maxwacht is set in initit Procedure initit Purpose To initialize variables used in this library and to initialize the PARSAM PROCEDURE initit meet Procedure meet Purpose To check the time it takes to fill the memories given the current settings 5 After a memory has been filled the number amp of the memory is given followed by the time it took to fill it in ms Note This is a revised version of the amp original by Roger van Galen Procedure Purpose Interface de de de de oe de PROCEDURE loopje nchan loopje To sample a given number of channels and collect a given number of samples nchan IN number of channels maxi IN number of samples maxi integer botte adcs Procedure Purpose Interface ge oe de Je PROCEDURE botte_adcs n_ botte_adcs To use the PARSAM as a straight ADC IN number of channels to sample integer startparsam Procedure Purpose Note
32. e Difference is that in this case the resulting string is returned as a third parameter in the parameter list whereas in C the second string is placed AT the END OF the first string In PEP array extension is not possible Interface sl IN first string s2 IN second string text OUT result string 36 PROCEDURE strcat sl s2 CONST string text REF string presskey Procedure Purpose presskey This is an overdeclaration of presskey in HWD ST5 HWC because OF some problems Difference is the position of the message ge de de de oP PROCEDURE presskey Procedure ing str Purpose asks string of maximum length from standard input length len with question given by text x_ and y _ are the screen coordinates where the question starts A boolean is used to indicate whether string is filled with at least one non space character Interface Kr YL IN screen position of message len IN maximum length of string 5 text IN message to display amp str OUT string to be filled filled OUT str has non zero contents PROCEDURE inq_str x_ y_ len nat2 text CONST string str REF string filled REF boolean inq_int ing_real ing_nat1 ing_bool se Procedures ing int ing real ing natl ing bool Purpose prints question on standard output text and reads the variable from standard input answer Text is printed at screen coordinates X_ y_ Interface Kr Y IN screen coordi
33. er With option D one can toggle the display of the Reynolds number flow rate and temperature on the screen This display is updated every two seconds and can be used to adjust the flow rate to obtain the correct Reynolds number 3 1 9 Measurements To start the measurements select option M in the main menu Before the measurements are started a number of settings are checked dd Menu level 2 Checking before measurements dd OK Processed data to VAX file name has been set OK Processed data to LDN file name has been set OK Raw data tot LDN file name has been set OK Output to any type of file OK Has tracker range been set OK Has pre shift been set OK Has range been calibrated OK Calibration for correct ADC OK Has amplifier gain been set NOT OK Calibration done with gain set to current value OK Has amplifier offset been set OK Calibration done with with offset set to current value OK Has PARSAM gain been set OK Calibration done with PARSAM gain set to this value OK Has angle of traverse been set OK Has angle of LDA been set OK Has pipe centre been determined Hit any key If anything is not correct the user has to go back and correct the error Once the first series of checks is passed some other checks are performed dd Menu level 2 Checking dd Checking sampling frequency Trigger frequency appears to be 100 Hz Data written to file at once Checking speed of
34. erages in LDA frame mom2_in IN 2nd moments in LDA frame mom3_in IN 3rd moments in LDA frame av IN OUT averages mom2 IN OUT 2nd moments mom3 IN OUT 3rd moments Remark su sv etc are assumed to be produced by 5 sommatie That procedure produces the actual moments av u av v av u u v v v av u v Author W Steenbergen A F Moene Data 08 07 1994 rev 13 7 94 03 10 1995 adjustment to use of mp os p_gain 21 11 1995 adjustment in computation of aaa PROCEDURE moments av_in ARRAY 0 OF real mom2_in ARRAY 0 0 OF real mom3_in ARRAY 0 0 0 OF real av REF ARRAY 0 OF real mom2 REF ARRAY 0 0 OF real mom3 REF ARRAY 0 0 0 OF real density Procedure density Purpose To compute density of water as function of temperature Interface temperat IN temperature in K return value density in kg m3 PROCEDURE density temperat real viscos de Procedure viscos Purpose To compute the kinematic viscoity as function of temperature Interface temperat IN temperature in K return value viscosity in m 2 s PROCEDURE viscos temperat real real Procedure reynolds Purpose To calculate Reynolds number from flow rate and temperature Interface t IN temperature in deg Celsius fl IN flowe rate in m3 hour amp rad IN radius of pipe in m PROCEDURE reynolds t fl rad real real calib_track Procedure calib_track Purpose To enab
35. es set set_sample Centre of pipe has been determined set_pipe_centre Experiment code been set set_expcode boolean Calibration information Date of calibration for each range calib_date ARRAY 1 7 OF integer ae de Time of calibration for each range calib_time ARRAY 1 7 OF integer PARSAM used as ADC during calibration calib_pars ARRAY 1 7 OF boolean Amplifier gain used during calibration calib_gain ARRAY 1 7 OF real Store raw and or processed data to VAX and or LDN Amplifier offset used during calibra calib_offset ARRAY 1 7 OF real PARSAM gain used during calibration calib_pgain ARRAY 1 7 OF real Has range been calibrated calib ARRAY 1 7 OF boolean Current sampling frequency freq integer Positions of pressure points dpx1 dpx2 real up ani Have dpxl and dpx2 been set set_dpx1 set_dpx2 boolean Do pressure measurements press_meas boolean Which transducer in use press_trans natl Names of pressure transducers press_name ARRAY 3 4 OF char Full scale range of transducers in press_full_scale ARRAY 1 2 OF real Has pressure transducer been choosen set_press_trans boolean Has transducer been calibrated calib_press ARRAY 1 2 OF boolean Date of calibration calib_press_date ARRAY 1 2 OF intege Calibration coefficients V a b press_coeff ARRAY 1 2 1 3 OF real Current number of samples sample Current
36. estroyed Issuing the options C or E will eventually lead one to the following menu FERE E AE AE FEAE FE EEE HEH FE E AE EH Ha FE E Ha EE Ha EH a EH aa EH a EH ETH RET HERAT HRA EH HE REET Menu level 4 Edit position table Ht FERE E AE AE HE AE AE FE FEAE HEH HEE EH EE Ha EE Ha EH AE EH aa EH aa EH AE HRA HET HRA EH RAH REE OPTIONS Al Add a point 18 Add more than one point Delete one point Delete more than one point Delete successful points Reset info on success of processing Show table Stop le na II bob wot OPTION Al To add one point to the list use option Al The user can enter the r R value for the point followed by a carriage return If one needs to add more points choose AM The sequence of points entered must be ended by typing a Q rather than a number To delete one or more points from the table one first needs to know the positions of those points this can be found out by showing the table on the screen option S With option DS all points for which the measurements have been completed successfully can be removed from the table When in the experimental setup menu the measurement mode option O is set set to pressure the menu looks like dd Menu level 2 Experiment setup dd OPTIONS O Measure mode now pressure E Code for experiment now mn076axx New name for setup file now gsd setup gsd Save setup to gsd setup gsd Retrieve setup from gsd setup gsd Number of samples fixed to 400
37. evel 4 Calibration of pressure transducer dd Open shunt valve have water level difference of approx 0 cm Hit any key V 4 3223446e 04 Close shunt valve do not move bottle Give exact height in cm 1 Hit any key V 4 3711846e 04 Set water level to approx 44 0 cm Give exact height in cm a2 Hit any key V 4 7619047e 04 Set water level to approx 79 2 cm Give exact height in cm Ees Hit any key Vv 5 2991451e 04 a 26985410 b 942 91589 c 752190 19 The pressure difference used for the calibration is applied using two small bottles connected to the transducer through plastic tubes see figure 3 1 One of the bottles is at a fixed height in a standard on the table The other is mounted on a vertical scale with a nonius along which it can be slided First one has to determine the voltage at zero pressure difference with open shunt valve Then one keeps both bottles at the same height and closes the shunt valve to obtain the first actual reading Subsequently the bottle at the vertical scale is moved to two lower positions Approximate heights are indicated by the program depending on the transducer to be calibrated Exact heights to a precision of 0 01mm must be entered The final result are three coefficients in a second order polynomial Ap a bV cV After the calibration the pressure transducer menu is returned to Here one can set the axial position in m of the two pressure taps in the pipe Furthermore the
38. figuration of reference and scattering beam see figure 2 4 Consequently if the mean flow velocity along the pipe axis is denoted by U the Doppler fre quency to be expected is f 1 2 U5 sin 9 where n is the refractive index of water 1 33 A is the wavelength of the light used 632 8 nm and 0 is the half angle between the scattering beam and the reference beam for the f 160mm lens this is about 8 Thus the mean Doppler frequency is about 2 1 10 Hz ms The above rule can be summarized by writing the relationship between frequency and velocity in vector notation fi _ an any Ui Na anj U2 ey where f and fz are the Doppler frequencies for the two trackers U is the velocity component parallel to the pipe axis and perpendicular to the optical axis of the laser U is the velocity component perpendicular to the optical axis of the laser and perpendicular to the plane formed by the two reference beams a11 a12 and a are matrix components with values of about 2 1 10 Hz ms and a is about 2 1 10 Hz ms The tracker range should be chosen large enough to allow for large turbulent velocity fluctua tions The frequency shift should be chosen such that the low mean velocities occuring in the wall layer are within the range of the tracker whereas the zero velocity of the wall is outside the tracker range In some cases these two requirements can not be made simultaneously one could think of very low wall
39. first with the measurement volume near the pipe centre and for the intersections at the diode side of the pipe and at the laser side of the pipe FERE E AE AEAEE AE FE FEAE FE FE HE AE FE FE FE AE FE FE E AE FE FE E AE FE AE E AE FE FEAE FE FE FE AE FE FE FE FE FE EH E AE AE AE E AE AE FE AE AE AEE AE AE AEAEE E HRA EEE EEEE EE Find centre of pipe FERE E AE AE AE AE FE FE FEAE HEH HEH HEE Ha EE Ha EH a Ha Ha EH EH RA HR HRA TH E EEEE EE Situate measuring volume near pipe centre Menu level 4 OPTIONS Unnnn Dnnnn Fnnnn Bnnnn Cc OPTION C move move move move nnnn nnnn nnnn nnnn continue steps steps steps steps up down forward backward Beam wall intersection at diode side Position left intersection Position right intersection distance 4 8745079 3 4467914 3 4468038 wall_pos 1 0 wall_pos 1 1 Hit any key Situate measuring OPTIONS Unnnn Dnnnn Fnnnn Bnnnn Es OPTION C 2 45 By 54 volume near pipe centre move move move move nnnn nnnn nnnn nnnn continue steps steps steps steps up down forward backward Beam wall intersection at laser side Position left intersection Position right intersection distance 4 8745079 3 4467914 3 4468038 wall_pos 2 0 wall_pos 2 1 Hit any key 2 23 3 43 to wall to wall Subsequently the measurement volume is moved to an off axis position vertically dd Find cent
40. gent of the slope to obtain the angle over which the laser optics should be turned around the optical axis The ultimate goal is to reduce the slope such that the misalignment is less than 0 1 degree This alignment does not need to be repeated when the laser optics are turned for measurements at 45 degrees Option C in the alignment menu gives the sub menu for determining the centre of the pipe gt To get rid of the graph on the screen press lt RETURN gt followed by Ctr1 G 26 dd Menu level 3 Centre and radius of pipe FERE E AE AE HE AE FE FE FEAE AE FE HE AE FE FE FE AE FE FE E AE FE FE E FE FE HE AE AE FE FEAE FE FE FE AE FE FE FE FE AE E AE AE AE E AE EE E AE AE FE AE AE AE AE AE AE AEE EE EEE EEE EEEE OPTIONS S R Q OPTION S Start procedure for pipe centre Set radius of pipe manually now 20 00 mm Stop With option R one can set the radius of the which is a by product of this alignment manually to the nominal value either 20mm or 35mm It is good practice to do this after the determination of the centre of the pipe For this alignment the laser optics is moved such that the measurement volume is in the neighbourhood of the pipe centre The laser is turned on but the scattering beam is not needed Using the telescope mounted on top of the plate where the diodes are mounted the horizontal positions in mm of the intersections of the two reference beams with the pipe wall are measured This is done
41. hat is smaller than a given real value Interface r in real value return value the requested integer value Remark This procedure exists for compatibility reasons return value requested integer value Procedure ceil Purpose To return the smallest integer value that is than a given real value Interface r IN real value PROCEDURE ceil r real integer pow Procedure pow Purpose To return x y where x should be a positive integer and y should be an integer Interface x IN base y IN exponent return value x y real Remark This procedure is needed since PEP does not allow though it should negative exponents PROCEDURE pow x y integer real determinant3 Procedure determinant3 Purpose to determine determinant of 3x3 matrix Interface ccc IN 3x3 matrix return value determinant of ccc de de de oe de PROCEDURE determinant3 ccc REF ARRAY 1 3 1 3 OF real real determinant2 Procedure determinant2 Purpose To determine determinant of 2x2 matrix Interface matr IN 2x2 matrix return value determinant of matrix de de de oe de 39 largePars_gain_a PROCEDURE determinant2 matr REF ARRAY 1 2 1 2 OF real real Procedure absr Purpose To return the absolute value of a real Interface r IN real of which to determine absolute value return value absolute value de de de de oe de PROCEDURE absr r real 3 2 9 PARSLIB se Library parslib Purpose Procedure
42. hrough the positions stored in the position table or give other values for r R 29 3 1 10 Stepper motors The stepper motors can be controlled from the stepper motor menu option C in the main menu AEREE AE AEE AE AE FE FEAE AE FE HE AE FE FE E AE FE FE E AE FE FEE FE FE FE AE FE FE FEAE FE FE FE AE FE FE E FE FE FE E FE AE E AE FE AE E AE AE FE E AE FEAE FE AE AE AE E E EAEE E E E EEEE EE Menu level 2 Control of stepper motors HaHa FE HE AE HEH FE E AE FE FE E AE FE EE Ha EH aE FE FE AE EH aa EH a EH EH RET HRT HRA EH HTH REE OPTIONS Switch on stepper motors Make steps in y or z direction Make steps to r R position Move to pipe centre Set y_pos to a value now 0 Set z_pos to a value now 0 Stop OPTION S Option O is equivalent to what happens when one starts the menu system and the program asks whether one wants to switch on the stepper motors The program will store the readings of the position en coders Then one will be asked to switch on the stepper motors and to subsequently hit a key The program will now determine the displacement of the encoders due to the switching on of the stepper motors and correct for the displacement This procedure is used to ensure that once the LDA optics have been aligned properly this alignment can be used even after the PEP system has been switched off For this reason it is also advisable that whenever the computer is switched off the optics are brought in such a position that measure
43. ial component Or one could use measurements over a different traverse to study asymmetries in the flow The radial positions at which measurements are made are defined in the so called position table A separate menu is available to manipulate this table dd Menu level 3 Position table dd OPTIONS TN Change name of position table file now gsd posfil gsd Retrieve position table from gsd posfil gsd Save position table to gsd posfil gsd Edit position table Create new position table Show current position table Set position pointer to specific value now 3 Stop OPTION E Position tables can be stored in a file The name of this file can be set with the option TN default name gsd posfil gsd the file can be saved with TS and retrieved with TR The position table consists of an array with two columns One column contains radial position expressed as r R and the other column contains a flag that signifies whether the measurement of velocity data has been completed successfully for that positions Throughout the program the position pointer is maintained a number that points to the next position for which measurements will be done in this menu it can be reset to a specific value option P With the option S one can show the current position table on the screen Using the options E or C one can edit the position table In the case of creating a position table the user is first asked whether the existing table may be d
44. ilable for both diameters The fundamental unit length is 0 95m and most sections have a length which is a multiple of this Figure 2 3 Dimensions of the pipe contraction sizes are in mm the pipe wall replaced by film Water can exit from the chambers through a small pipe system attached to the bottom of the measurement section This small pipe system is also used to keep the water in the chambers at a slightly lower pressure than the water in the pipe by connecting the small system to a the main pipe system at a position slightly downstream of the measurement section where the static pressure is lower due to the pressure drop needed to keep the water flowing against friction To allow air in the bolts at the top of the chambers of the measurement section should be opened The system is refilled with water from a desalination unit This water is fed into the system though a tap that is located near the thermometer T In order to actually fill the system valve V4 needs to be open as well as the tap below valve V3 to let the air escape from the system While the horizontal pipe section is filling water should be allowed into the chambers of the measurement section This is done through a small pipe system attached to the measurement section The water needed for this is drawn from the same supply that is used to fill the entire system The water level in the chambers should more or less follow the level in the pipe Once the
45. laboratory For the y and z movement use is made of stepper motors that allow movements with a step of 0 02mm to be made The number of steps is checked by position encoders connected to the shafts of the stepper motors End switches are used to restrict the movement of the plate with optics to a bounded region For the vertical movement counter weights are used in order to drastically reduce the amount of power needed to traverse the optics vertically 2 2 3 Miscellaneous measurements Besides the velocity measurement using the LDA some extra quantities are measured water temper ature and flow rate The water temperature is monitored using a thermal diode of which the signal is converted to a voltage signal using a Laumann temperature display The flow rate is measured by an Altometer magnetic flow meter SC 80 AS which has a current output proportional to the flow rate This current is converted to a voltage by passing the current through a resistor of 470 1 The temperature and flow rate signal are digitised using a 12 bit ADC Incidentally measurements of pressure drop have been done To this purpose pressure taps with a diameter of 0 5mm are present in the pipe wall These taps can be connected to one of the two pres sure transducers Validyne DP15 30 or DP45 16 which have a range of Ap lt 880 and 35mm H20 respectively The signal of these pressure transducers is passed through an amplifier to a conventional ADC 11 lens 2
46. le thus using the forward scattered light The laser that is used is a 15 mW He Ne laser manufactured by Uniphase The optics mounted before the laser provide two reference beams and a scattering beam see figure 2 4 and 2 5 The scattering beam is shifted in frequency 40M Hz by a Bragg cell the Bragg cell is driven by a signal from one of the frequency shifters Dantec 55N12 Two different front lenses can be mounted on the sending optics one with a focal length f of 160mm and one with f 80mm The beams pass through the measurement section and the light of the reference beams and the light scattered in the direction of the reference beams is collected by lenses with a focal length of 60mm passes through a pinhole and finally hits the photo diode the pinhole is part of the housing of the diode Dantec 55L11 In the shifter the signal from the diode is shifted back by a frequency which is the sum of the 40M Hz pre shift of the Bragg cell and a positive or negative frequency needed for an optimal use of the range of the tracker From the shifter the signal is passed to the Dantec tracker 55N21 where the high frequency information is converted to a voltage between 0 and 10 V The analog signal from the tracker is digitised using the parallel sampler PARSAM developed by Technical Laboratory Automation Group at TUE see Smeets and Nijmweegen 1993 Since the PARSAM has an input voltage range of 10V to 10V a programmable amplifier buil
47. le user to calibrate a tracker i e fill a part of the calibration table Method The user is prompted to set the signal generator to a frequency Is this has been done samples are collected and the deviation of the voltage from the ideal inear calibration is determined This procedure is repeated 3 times Then a second order polynome is fitted through the deviations for three frequencies Interface range IN the freq ranges of each of the two trackers to be calibrated PROCEDURE calib_track range ARRAY 1 2 OF natl 3 2 8 MATHLIB Library mathlib Purpose Contains mathematical procedures Author Arnold Moene Date fall 1994 Revision october 1995 addition of deg2rad and rad2deg Required libraries none deg2rad Procedure deg2rad Purpose Interface To convert an angle in degrees to radians r in angle in degrees return value angle in radians ge oe de oe PROCEDURE deg2rad r real real Procedure rad2deg Purpose To convert an angle in radians to degrees Interface r in angle in radians return value angle in degrees PROCEDURE rad2deg real real return value the requested integer value Procedure floor Purpose To return largest integer that is smaller than a given real value Interface r in real value PROCEDURE floor r real integer Some libraries use trunc instead of floor Procedure trunc Purpose To return largest integer t
48. m of these samples the tracker was locked locked the lock signal was above the lock limit given after option L in raw ADC output the number of samples to be taken is increased in order to retain the originally requested number of samples If this final number of samples if more than the maximum multiple given following option X the position is skipped for further measurements If for more than 75 of the samples the tracker was locked the original number of samples will be gathered e If the position is not skipped the measurements will be made The quality of the data will be assessed again the program requires the tracker to have locked for more than 75 of the samples If the data quality is sufficient the data will be processed and stored to file Internally a flag will be set that this point was completed successfully which can be done manually with option F Note that the processed data are stored in ASCII format but in a binary file EPEP does not permit the writing of lines longer than 128 characters to an ASCII file e After completing measurements at a given point the program proceeds to the next point in the position table For the raw data the procedure is simpler no check on the quality of the data is made data are taken and written to file The format of this binary file is given in appendix A 2 When manual measurements are chosen option M data are taken for one position at a time and the user can either cycle t
49. mber and other data on screen stop_show_r To stop display of Reynolds number and other data on screen PROCEDURE stop_show_r 3 2 6 IOLIB se Library iolib Purpose This library contains IO functions Author Some functions are based on work by Roger van Galen Other procedures have been written by Arnold Moene Date Fall 1994 Required libraries HWD st5 HWC Library only tested for PEP030 2 30 0 de oe de de oe de de de do ae Procedure write real arr Purpose To write a real value formatted by writeln to a Character array At an end of line a carriage 5 line feed is added Interface r IN real value arr IN OUT array to write to pos IN OUT next position in array 5 eol IN is this end of line PROCEDURE write real arr r real arr ARRAY 0 OF char pos REF integer eol boolean strcpy Procedure strcpy Purpose PEP implementation of C function strcpy Interface strin IN string to be copied from strout OUT string to be copied to strout REF string rocedure beep urpose To ring the terminal bell mu or beep se Procedure put_text Purpose writes text to standard output starting at given screen location Interface x IN x position on screen to start y IN y position on screen to start text IN string to put on screen PROCEDURE put_text x y nat2 text CONST string strcat Procedure strcat Purpose a PEP implementation of the C function strcat Not
50. me position after switching on of stepper motors Method In this respect the values returned by the encoders give the absolute position The values before and after switching on of the stepper motors are compared If they differ more than one step of either of the stepper motors the position is corrected Interfac x IN x position on screen of message amp Vs IN y position on screen of message PROCEDURE switch_on x_ y_ nat2 A File formats A 1 File format for processed data The processed LDA data are written to an ASCII file However this file is a binary file due to the limitations in PEP on the number of characters on a line Each line is written as an array of characters with a carriage return line feed as the last character This arrangement implies some postprocessing before the file can be read as a normal text file After the data of a given radial position have been processed the data of all radial positions including the last will be written to file Data of one radial position occupy one line in the output file see table A 1 Here u is the velocity component in the axial direction and v is the velocity component prepen dicular to both u and the plane through the two reference beams T is the water temperature Q is the flow rate Re is the Reynolds number based on bulk velocity and pipe diameter dp d0z is the axial pressure gradient if measured u is the friction velocity and yt is the distance from the
51. ment volume is at the centre of the pipe this corresponds to y pos Oandz pos 0 Option S gives the following menu FERE E AE AE EAE FE FE HE AE FE FE HE AE FE FE FE AE FE FE E AE FE FE E AE FE FE E AE FE FEAE FE FE FEAE FE FE FE AE FE FE E AE AE E E AE FE E E AE AE E AE FEE AE FE AE E AE AE AE E AE FE E AE AE HE E EEEE Menu level 3 Move steps in y and z direction dd OPTIONS Unnnn move nnnn steps up Dnnnn move nnnn steps down Fnnnn move nnnn steps forward Bnnnn move nnnn steps backward to wall Q stop OPTION Q The steps mentioned in the menu are steps of 0 02mm so there are 500 steps in a cm To make a move to a specific radial position in the direction of the traverse given in the setup menu see 3 1 2 choose option R in the stepper motor menu dd Menu level 2 Control of stepper motors dd OPTIONS Switch on stepper motors Make steps in y or z direction Make steps to r R position Move to pipe centre Set y_pos to a value now 0 Set z_pos to a value now 0 O S R Cc a Z Q Stop OPTION R Give r R value 0 Option C is equivalent to choosing r R 0 for option R Setting the y position and z position options Y and Z respectively does not move the laser optics but just shifts the internal coordinate system Use with care one might loose the correct alignment 30 3 2 Libraries A number of special purpose libraries in EPEP have been developed for use with the menu sys
52. names of the subdirectories in the directories mentioned before The names of the output files are formed automatically from the device name and the experiment code set in the setup menu see 3 1 2 With options SLR and SLP one can choose the data to be saved at LDN either raw data binary files with time series of both trackers and optionally 19 Range Lower frequency kHz Upper frequency kHz 1 1 10 2 3 33 3 10 100 4 33 333 5 100 1000 6 300 3300 7 1000 10000 Table 3 1 Number of the tracker ranges output data of the lock channel of the trackers or processed data ASCII file of means variances etc With SVP one can choose to store processed data on the VAX device When raw data are stored some extra options are given dd Menu level 2 File and data menu dd OPTIONS DV change standard VAX device change standard LDN device name processed data file on VAX name raw data file on LDN now gud mn076axx gsr name processed data file on LDN now gud mn076axx gsd now gsd Save raw data to LDN ON now gud now gsd mn076axx gsd Save processed data to LDN Save processed data to VAX Store tracker lock data Block type Nominal LDN rate byte sec Quit to main menu contin 1 block 45000 OPTION B 1 contin 1 block 2 contin more blocks 3 non contin blocks Block type 2 One can request to store the output of the lock indicators of the trackers option L With opti
53. nates of text text IN text to display answer OUT the variable read PROCEDURE ing int x y_ nat2 text CONST ARRAY 0 OF char answer REF integer PROCEDURE ing real x y_ nat2 text CONST ARRAY 0 OF char answer REF real PROCEDURE ing natl x y_ nat2 text CONST ARRAY 0 OF char answer REF natl PROCEDURE ing bool x y_ nat2 text CONST ARRAY 0 OF char answer REF boolean clear_presskey Procedure clear_presskey Purpose removes line hit any key written by procedure presskey defined above in this file ge oe Je Je PROCEDURE clear_presskey make_title Procedure make_title Purpose writes a menu title to screen adding an indication of the level of the current menu relative to main menu 5 The procedure title can be found in HWD st5 HWC Interface lev IN menu level text IN menu name PROCEDURE make_title lev natl text CONST string write_date Procedure write_date Purpose writes a date passed as YYYYMMD in DD MM YY format to standard output de oe oP oP PROCEDURE write date dat integer clear line de Procedure clear_line Purpose goes to specified line on screen and overwrites existing text with spaces Interface n IN line number to clear PROCEDURE clear_line n nat1 readbool ae Procedure readbool Purpose To read in a file a 1 or 0 and sets a boolean to true or false respectively Interface f IN file to read from b OUT boole
54. ndly either a straight pipe with a diameter of 70mm can be used or a contraction 70mm 40mm can be mounted after some length of 70mm pipe Then about 4m of 40mm pipe can be installed downstream of the contraction The transition back to a pipe of 70mm is made through a vessel The pipes of both diameters are divided in pieces of different lengths Due to this modularity the configuration of the system in terms of the axial position of the contraction as well as the measurement sections see below is flexible Velocity measurements both mean flow and turbulent quantities can be made using a 2 dimensional Laser Doppler Anemometry LDA system The optics can be traversed to make measurements at any radial position in the pipe Through the combination of measurements with the optics mounted un der three different angles but perpendicular to the pipe axis the full velocity vector as well as the full Reynolds stress tensor can be obtained Optical access to the flow is possible through specially designed measurement sections in which the pipe wall has been replaced by a thin transparent sheet These measurement sections are available both with a pipe diameter of 70mm and 40mm In the following chapters the actual pipe flow system is described as well as the equipment used to operate it chapter 2 This report describes the situation as it was in the Warmte en Stroming build ing from which the Fluid Dynamics laboratory moved in the spring of
55. o continuously measure temperature flow and pressure difference Interface This process modifies the global variables t_end fw_en and dp_end Remarks The process keeps some kind of running mean The sampling interferes with the control of the steppen motors so abort flowtemp before moving steppenmotors Revision 28 05 96 now data are stored in an array a_dep etc and average over array is computed when needed in seperate routines dp_end etc de oe de de de ge oP de oP de oP do PROCESS flowtemp 5000 show_reynolds should be updated sec Procedure show_reynolds Purpose writes Reynolds number flow and temperature to screen updates every five seconds until a key is pressed Interface x IN x coordinate of upper left corner of box where data are displayed y IN y coordinate of upper left t IN time interval after which data PROCESS show_reynolds 10000 Measurement is externally triggered Procedure temp Purpose To get one sample of water temperature Interface return value temperature temp shares signal s with flow Remarks Temperature is measured via ADC adc_flow channel 1 PROCEDURE temp nat2 fbw Procedure flow Purpose To return one sample of the flowmeter Interface return value flow Q 10 N 4095 R Qmax Imax met R 471 Ohm Qmax 78 Imax 20mA flow wordt gemeten via ADC adc_flow kanaal 1 Procedure start_show_r Purpose To start display of Reynolds nu
56. oltage when shunt valve is open 5 no_shunt IN voltage when shunt valve 5 is closed PROCEDURE cal_corr a F REF real shunt no_shunt real meas_press Procedure meas_press Purpose To measure the output voltage of the pressure transducer Interface press_sample IN number of samples to use avg_dpv OUT output voltage REF real Procedure ustar Purpose To determine u from a given pressure gradient in mH20 m and a radius in m Interface pressg in pressure gradient in mH20 m rad in radius in m return value PROCEDURE ustar pressg rad Procedure yplus Purpose To compute y from a given radial position in r R pressure gradient radius and temperature Interface pressg In pressure gradient mH20 m rr IN r R rad in radius m temp in temperature deg C return value y PROCEDURE yplus pressg rr rad temp real real press_grad Procedure Purpose press_grad To determine the pressure gradient between two points of which the positions are given by dpxl and dpx2 in m H20 m The distance is determined from the global variables dpxl and dpx2 the reading of the pressure transducer is taken from dp_vao_end measured in process flowtemp and the pressure is determined from dp_vao_end and the calibration factors for the transducer used return value Method Interface pressure gradient in m m de de de de de oP de de de ge
57. on B the way in which raw data are written to file can be chosen Option 1 continuous one block implies that all data of a times series are written to file in one operation This requires that all data can be stored in the memory 4M b in the present setup of the MPS system at once If more data will be gathered than can be stored at once one can chose to write the data in blocks After one part of the PARSAM memory 512kB has been filled and new samples are stored in the other part of the memory the data from the first part of memory are written However this only works when the data can be written to disk faster than that they are gathered in the other PARSAM memory Therefore one needs to set a nominal speed of the LDN connection option R If the sampling rate is too high to allow the data to be written to file in time one has to choose option 3 non continuous blocks This will result in chunks of time series that are not contiguous in time Whether the choice for a given block type is realistic will be tested before the measurements start 3 1 4 Trackers Option T in the main menu brings the user to the tracker menu Here one can choose the settings for the trackers The range can be choosen by number see table 3 1 Some guidance in the choice of the tracker range can be given with te following rules 20 The Doppler frequency is for each reference beam is proportional to gt 2 of the flow velocity along the pipe axis due to the con
58. on M Repeat the last three steps for all combinations of pressure taps required 24 Connect the tubes of the transducer to the pressure taps to be used and flush any air from the 3 1 6 ADC and amplifier menu Selecting option A in the main menu gives the ADC and amplifier menu Here one can choose which ADC Analog to Digital Converter one wishes to use option C either PARSAM or the so called old ADC Ha EH a EH a EE HH HE AE EH aa FE E FE FE a EH FE AE EH AE EE aE EE HE EE EEE RT HE AAA Menu le vel 2 ADC and amplifier setup dd OPTIONS RSAM P or old ADC 0 Choose type of ADC n Choose gain for amplifier now 4 Choose offset for amplifier now 2 50 V Choose gain for amplifier of PARSAM now 1 Quit to main menu ow PARSAM Ep Option G gives the possibility to set the gain of the programmable amplifier This is used to re scale the output of the tracker 0 10V to the input range of the PARSAM 10 10V dd Menu lev el 3 Amplifi er gain menu dd OPTIONS 0 1 2 33 4 5 6 7 multiplier multiplier multiplier multiplier multiplier multiplier multiplier multiplier 0000000 0000000 0000000 0000000 8 0000000 10 000000 15 000000 20 000000 1 2 4 6 Give index of required gain 1 The gains given in the menu are nominal values whereas in the actual data processing exact measured gain values are used Besides
59. optics are under an angle of 45 degrees a block with an angle of exactly 45 degrees can be placed on top of the brass plate 25 Assuming that the laser is mounted in the traversing system such that the optical axis is perpendicular to the axial dimension of the traversing system the latter will now be parallel to the pipe axis e The traversing system needs to be exactly horizontal both in the direction of the pipe and in the direction perpendicular to 1t This is checked with a water level The four feet on which the traversing system rests can be adjusted independently e The laser beams need to be adjusted such that the velocity v v2 resulting from the refer ence beams 1 and 2 respectively is exactly parallel to the pipe axis and v v2 is exactly perpendicular to it option H e The coordinate system of the pipe needs to be linked to that of the traversing system at one point the pipe centre option C FERE E AE FEE E AE FE FEAE FE FE HE AE FE FE HE AE FE FE E AE FE FE E AE FE FE E AE FE FE E FE FE FE AE FE FE FE FE AE FE E AE AE E E FE AE E E AE FE E AE FE E AE AE AE E AE AE AE E AE TE E HRT ERE Menu level 2 Positioning of laser dd OPTIONS H Horizontal lining of laser Cc Find centre of pipe Q Stop OPTION H Choosing for the horizontal alignment gives the following menu dd Menu level 3 Horizontal lining of laser dd OPTIONS L Cc Q OPTION L Perform horizontal lining Calib
60. owing libraries will be loaded in this order e PEP ST240 PTC e GSD PLOTVT GSC e GSD ST7 GSC e GSD MATHLIB GSC e GSD IOLIB GSC e GSD LDADEC GSC e GSD PARSLIB GSC e GSD ADCLIB GSC e GSD LDALIB GSC e GSD FLOWLIB GSC e GSD DPLIB GSC e GSD STEPLIB GSC e GSD CFGLIB GSC 16 After the libraries have been loaded you type RUN MENU to start the system When the menu system was not terminated properly the previous time it was run a temporary file may still be present default name gsd tempfile gst The program will ask whether you want to read settings and data from this file Next the program will ask whether you want to switch on the stepper motors If you answer Y the program will store the readings of the position encoders Then you will be asked to switch on the stepper motors and to subsequently hit a key The program will now determine the displacement of the encoders due to the switching on of the stepper motors and correct for the displacement This procedure is used to ensure that once the LDA optics have been aligned properly this alignment can be used even after the PEP system has been switched off For this reason it is also advisable that whenever the computer is switched off the optics are brought in such a position that measurement volume is at the centre of the pipe this corresponds to y pos 0 and zpos 0 After the menu system has started you will be presented with the main menu
61. r do3 boolean AT sommatie_code 0 check_lock Procedure check_lock Purpose to remove data from two velocity arrays for 5 which not both trackers did lock Interface u dat v_dat IN OUT nat2 data to be checked u_loc v_loc IN lock data lock_limit IN count above which locking is on new_samp IN OUT number of samples PROCEDURE check_lock udat vdat uloc vloc lock_limit nat2 new_samp REF integer ARRAY 0 OF nat2 AT check_code 0 track_corr ae Procedure track corr Purpose To apply calibration curve to tracker data Interface uu IN OUT array with ADC data from u tracker vv IN OUT array with ADC data from v tracker sample IN number of samples in arrays ampmp IN multiplier of amplifiers ampos IN offset of amplifiers parmp IN multiplier of PARSAM nil c IN count value at 0 Volt vper_c IN number of counts per volt rl IN range of tracker 1 r2 IN range of tracker 2 5 cof IN calibration coefficients PROCEDURE track _corr uu vv ARRAY 0 OF nat2 sampl integer ampmp ARRAY 0 OF real ampos ARRAY 0 OF real parmp ARRAY 0 OF real vper_c real ril ri2 natl cof ARRAY 0 OF real nul_c nat2 AT corr_code 0 Procedure moments Purpose conversion OF moments 1 st 2 nd AND 3 rd from 5 ade counts in lda frame to real world velocities 5 and dir Interface Global variables used scf mp os f_s def_range and rangeindex av_in IN av
62. rate tracker range 2 calibrated Stop For the horizontal alignment of the laser a brass plate is mounted on top of the measurement section as for the horizontal placement of the measurement section itself On top of the brass plate a perspex platelet is placed This will serve as a scattering object with a known direction of its velocity viz horizontal The laser optics have to be moved such that the measurement volume coincides with the vertical face of the perspex platelet at the side of the laser The LDA velocity measurements will be performed with tracker range 2 and the menu offers the option to calibrate the tracker at this range Furthermore one has to ensure that the shift frequency set at the shifter is identical to the one set in the tracker menu see 3 1 4 a useful value is 10000Hz A useful sampling frequency for these measurements is 1000Hz 1000 samples are taken The actual alignment procedure implies six measurements of the velocity of the platelet which is moved by hand in the forward flow direction Only measurements with sufficient quality viz a minimum number of samples for which the tracker locked are used After the six measurements a graph is shown on the screen showing the relationship between the horizontal and vertical in laser optics coordinates velocity on the horizontal and vertical axes The slope of the line gives the slope of the laser optics relative to the horizontal Compute the arctan
63. raw_type block _d boolean whether the storage type has been changed Procedure eval_ raw type Purpose To evaluate whether the requested raw data storage type is possible with respect to MPS memory and LDN speed Interface return value a boolean indicating PROCEDURE eval_raw_type boolean calc_maxsamp se declared in ldadec Procedure calc_maxsamp Purpose To compute the maximum number of samples in the nat2 and or integer arrays used for sampling in measmen Note Most variables used here are globals PROCEDURE calc_maxsamp order pos ae Procedure order_pos Purpose To sort a position table and remove double or deleted items having value no_value Interface table IN OUT position table succ IN OUT success flags n IN OUT length of table REF ARRAY 0 OF real REF ARRAY 0 OF boolean REF nat2 PROCEDURE order_pos table succ n midden_straal ae Procedure midden_straal Purpose To determine coordinates in LDA reference frame of centre of pipe Interface posl IN measured relative position of intersection of film and reference beams pos2 IN idem pos3 IN idem midden OUT y z position of centre of pipe PROCEDURE midden_straal posl pos2 pos3 ARRAY 2 OF integer midden REF ARRAY 2 OF integer lens_choice de Procedure lens_ choice Purpose To update parameters that depend on the focal length of the lens used In
64. re measurements Author Wiendelt Steenbergen Arnold Moene Date 1993 1995 Notes diode 1 component U V diode 2 component U V with V vertically upward Required libraries HWD st 7 HWC GSD iolib GSC GSD ldadec GSC GSD parslib GSC GSD adclib GSC Required compiled code GSD sommatie GSO GSD trackcor GSO GSD checkloc GSO Library tested only for PEP030 2 30 0 de de de de de de oP de oP de de dP dP dP dP de de de dP oP Je rocedure sommatie urpose To calculate averages wm Wo variances and covariances of two signals with value between 0 4095 Interface av OUT averages of a and b mom20 mom21 OUT 2nd moments mom300 mom301 OUT 3rd moments mom310 mom311 OUT 3rd moments underflow OUT number of samples with underlow overflow OUT number of samples with overflow dat_a dat_b IN arrays with ADC data psample IN number of samples do3 IN should I calculate 3rd moments Remark Each datapoint is checked for overflow and underflow and the number of accurences is exported the use of one dimensional arrays for mom2 and mom3 is due to the incapability OF the pep compiler to deal properly with multi dimensional arrays PROCEDURE sommatie av ARRAY 0 OF real mom20 ARRAY 0 OF real mom21 ARRAY 0 OF real mom300 ARRAY 0 OF real mom310 ARRAY 0 OF real mom301 ARRAY 0 OF real mom311 ARRAY 0 OF real underflow overflow REF integer meet_a meet_b ARRAY 0 OF nat2 psample intege
65. re of pipe dd Situate measuring volume off centreline Menu level OPTIONS Unnnn move nnnn steps up Dnnnn move nnnn steps down Fnnnn move nnnn steps forward Bnnnn move nnnn steps backward C continue OPTION C Beam wall intersection at diode side Position left intersection 3 48 Position right intersection 5 15 distance 9 7490158 wall_pos 3 0 6 8935828 wall_pos 3 1 6 8936076 Hit any key to wall 27 After this final measurement the program will report the distance from the pipe centre of the current origin of the coordinate system of the traversing system And more importantly it gives an estimate of the pipe radius This can be used to check the accuracy of the alignment The computed pipe radius should differ from the nominal value by less than 0 1mm 3 1 8 Preparation menu Some preparatory tasks before the measurements are started can be performed in the preparation menu option P in the main menu dd Menu level 2 Preparation for measurements dd OPTIONS C Check LDA signal at positions in table I Initialize values of flow temp D Display Reynolds number OFF Q Stop OPTION Q Option C enables the user to check the quality of the LDA signal at the radial positions stored in the position table edited in the setup menu see 3 1 2 Option I initializes the arrays with measurements of flow rate and temperature used for the computation of the Reynolds numb
66. s only one pressure transducer is used at a time However in principle it is possible to connect both transducers to the ADC each at a different input channel since both transducers have an individual amplifier 13 diode 55 L 11 diode 55 L 11 PM in shifter 55 N 12 mixer out PM in shifter 55 N 12 mixer out 40 MHz output tt Bragg cell oscilloscope HAMEG HM 204 2 photo detec in tracker 55 N 21 analog out lock out photo detec in tracker 55 N 21 analog out lock out laser Uniphase 1133P Analog in 0 trig in Parsam PAC power supply PLI PL2 Uniphase in out in out PLI PL2 programmable Parsam PPC puls generator amplifier Phybus BNC cable other cable location where to disconnect when disassembling the system Figure 2 7 Connections for the signal processing electronics 14 stepper motors end switches incremental encoders horizontal vertical a ee ij A AA ME 1 2 je lt 2 stepper motor power supply 12 en mn en oel 01 O1 oe Legend steppermoter interface dual position decoder 8 mmm location where to disconnect when disassambling the
67. s to control ParSam Author Most of this library is due to Roger van Galen Some additions by Arnold Moene Date Fall 1994 Required libraries none Required compiled code GSD split GSO Note Library only tested for PEP030 2 30 0 de Procedure split Purpose To split pairs of samples stored as integers into 2 2 byte naturals Note This is a compiled procedure Interface g_ IN array with integers pd_ OUT array of 2 byte nats 5 n IN number of samples PROCEDURE split g_ n_ ARRAY 0 OF integer pd_ integer AT parcomcode 0 ARRAY 0 OF nat2 II pars_gain_all Procedure Purpose To set gains of all channels to same value Method The gain is set to 2 v_ Interface v_ IN power of 2 to set gains to PROCEDURE pars_gain_all v_ integer pars_gain Procedure pars_gain Purpose To set gain of specified channel to specified value Method Gain is set to 2 v_ Interface nr_ IN channel number 5 v_ IN power of 2 to set gain to PROCEDURE pars_gain nr_ nat2 v_ integer n_pars_gain n_pars_gain Procedure Purpose To set gain of specified range of channels to specified value Method Gain is set to 2 v_ Interface k1_ IN first channel number R2 IN last channel number 5 Mz IN power of 2 to set gain to PROCEDURE n_pars_gain kl_ k2_ w_pars_gain w_pars gain To read current gain of specific channel Interface nr_ IN
68. t by Jan Niessen is used to re scale the signal from the tracker see section 3 1 6 The output signal of the lock indicator of the tracker is fed directly to the PARSAM The PARSAM uses a 12bit analog to digital converter ADC The choice to use a PARSAM in this experiment rather than a conventional ADC is based on two considerations e the PARSAM allows high sampling rates up to 25 kHz per channel e two memory buffers 512 kB each allow continuous operation so that large amounts can be gathered continuously 10 R1 R2 lens Figure 2 4 Confi guration of the laser beams front view left side view right S denotes the scattering beam and R1 and R2 are the two reference beams These two characteristics are mainly important when information on the temporal structure of the signal is required such as spectra 2 2 2 Traversing system The traversing system to move around the LDA optics is shown in figure 2 6 The plate to which the LDA optics are mounted can be turned around an axis that is parallel to the pipe over an angle of 50 to 50 This rotation mechanism in turn is mounted on a plate that can be moved horizontally y and the latter plate is mounted to a plate that can be moved vertically z This vertical movement is relative to a rigid frame 3 in figure 2 6 that can be moved horizontally in a direction parallel to the pipe within the outer rigid frame The latter is standing on the floor of the
69. terface IN focal length of lens PROCEDURE lens_choice f Procedure calc_transf_matrix 34 Purpose To determine the transformation matrix 5 from the discrete stepper motor frame y_pos z_pos to the continuous 5 reference frame of the pipe y 2 Interface lda a IN angle of LDA relative 5 to horizontal PROCEDURE calc_transf matrix lda a real save_setup Procedure save_setup Purpose saves value of most global variables 5 to a file Interface fname IN name of file to save to PROCEDURE save_setup fname CONST string retrieve_setup de retrieve _s Procedure etup Purpose To read values of most global variables 5 from a file Interface fname IN name of file to read from PROCEDURE retrieve_setup fname CONST string 3 2 4 DPLIB se Library dplib Purpose Procedure related to measurement and use of pressure gradients Author Wiendelt Steenbergen with some modifications by Arnold Moene Date y 1993 1995 Required libraries GSD 1ldalib GSc GSD iolib GSC GSD mathlib GSC 5 HWD st 7 HWC 5 GSD adclib GSC cal corr Procedure cal_corr Purpose To correct the calibration factors of the pressure transducer for the fact that the amp first reading was not at zero pressure amp difference The voltage measured with open shunt valve is used for the correction Interface ar Dye IN OUT calibration coefficients in dp a b V c V V shunt IN v
70. tor see figure 2 1 In practice the system is emptied between valve V3 and V4 The water is allowed to leave the system into the sewer through a tap in the bottom of the pipe upstream of the swirl generator while valves V3 and V4 are closed A tap just below valve V3 needs to be opened in order to allow air to enter the system When the water level has dropped such that air is entering the horizontal pipe section air should be allowed into the chambers of the measurement section that surround the part of constant head tank V3 V4 B Q S B gt K T V1 V2 storage tank ae P Figure 2 1 Schematic overview of pipe system after Steenbergen 1995 S swirl generator Q fow meter T temperature sensor V1 V2 V3 and V4 valves B rubber bellows P pumps four times Q MS70 S Q V MS40 C MS70 S A A Figure 2 2 Two confi gurations of horizontal pipe section straight pipe with a diameter of 70mm top or varying pipe diameter 70mm 40mm 70mm bottom S swirl generator Q fbw meter C contraction MS40 and MS70 measurement sections with internal diameter 40mm and 70mm respectively V vessel length m 0 31 0 369 0 374 0 475 0 81 0 95 2 85 3 80 4 70 D 70mm D 40mm 1 1 1 1 1 4 3 1 1 1 Table 2 1 Overview of the sections of pipe ava
71. u e 25 3 1 7 Positioning of the laser movi its a andes a 25 3 1 8 Preparation Mea 2 0 000 REE A ee 28 3 1 9 Measurements emitida eh ade ease Sa eel de Gate RE bs 28 3 1 10 Stepper motors eee 30 3 2 Librarie S eit es on eo ee ele ka eo hehe eh eh we 31 321 LDADEC oes aa er Rg AA ee we ee S 31 3 2 2 ADGCLIB vas err he we hae be a we eS 33 3203 CHGLIB hs aem aan he ky echt a oh Mo a ld dE a at ay ae 33 A A aai ea a a aa aa a a a Ai ea ae a e Baa aai 34 3 2 3 EFECOWLIB 0 2 ge Bary e e beneden rene Ses oT oe AS 35 326 JOLEIB 4 ee Boh Grok E E E dend ESE 36 3207 EDALIB ti BA A Bat EE ee Bea ene the 37 3 28 MATHEIB 2000 tense tale te deert EE de bot Ae Ae re 38 32 9 PARSLIB sr 50 inver dee ae bse ete ii ATRAL A 39 3210 STEP Ze eo ee A aen 41 A File formats A 1 File format for processed data A 2 File format of binary file for raw data o o e List of Figures 2 1 2 2 2 3 2 4 2 5 2 6 2 7 2 8 2 9 3 1 Schematic overview of pipe system o oo 2 2 ee ee 7 Two configurations of horizontal pipe section straight and with contraction 7 Dimensions of the pipe contraction sizes are in mm o o ooo a 8 Configuration of the laser beams oaoa a 11 Top view of the path of the laser beams ooa a 12 Traversing Mechas 13 Connections for the signal processing electronics o ooo 14 Connections for the traversing system
72. ugh the following pipe to obtain outputfile cat inputfile sed awk for i 1 i lt NF it print s i if NF gt 0 printf n gt outputfile 42 column N 0 ADA PWN KE nen ma o e a W N quantity unit r R u m s Vv m s wu m s vv m s ulv m s T C Q m3 hr Re dp dz mH O m Ux m s yt Nsamp Table A 1 Format of processed data fi le column oo ANU gn quantity unit X1 m X2 m Ap mH 0 Q m hr T C Re ap dz mH O m transducer 1 or2 Table A 2 Format of processed data fi le for pressure measurements name type version nat2 expcode character dat at ypenat2 ngroups nat2 description file version number experiment code info on block type etc number of radial positions in file CO Table A 3 Format of file header of binary file 43 meaning PEP name value ADC continuous blocks lock data old_adc_lock 0 old yes 1 yes con_l_lock 1 PARSAM yes 1 yes con_n_lock 2 PARSAM yes more yes nocon_n_lock 3 PARSAM no more yes old_ade_nolock 50 old yes 1 no con_l_nolock 51 PARSAM yes 1 no con_n_nolock 52 PARSAM yes more no noconn_nolock 53 PARSAM no more yes Table A 4 Codes for type of stored data The number of radial positions in the file ng roups is determined at the start of the measurements It may be possible that at the measurements have not been made for all radial positions and thus ngroups may
73. ump the water from the basin in the basement to the reservoir on the roof The pumps are switched on automatically when the water level in the reservoir has dropped below a prescribed level the upper and lower level of the water surface differ by about 5cm 2 1 2 Pipe sections The pipe sections used for the measurements consists of brass pipe with a wall thickness of 5mm The inner diameter is either 40 0 1mm or 70 0 1mm where the uncertainties are better than those required by the DIN standard the given uncertainties have been measured at the ends of the pipe sections The pipe sections are connected by specially designed couplings These couplings ensure that pipe walls of two coupled pipes are aligned within 0 05mm Two flow configurations can be studied a straight pipe with one diameter or a pipe with varying pipe diameter see figure 2 2 The measurement section with internal diameter 70mm has three chambers with optical access each 2 times 70mm apart whereas the 40mm measurement section has two chambers 4 times 40mm apart The availability of sections of pipe for both diameters is summarised in table 2 1 Figure 2 3 shows the dimensions of the pipe contractions used in the studies on strained turbulence 2 1 3 Filling and emptying the system When the pipe system needs to be modified e g measurement section to be installed at different axial position the system needs to be emptied at least between valve V4 and the swirl genera
74. valve V2 e Let the water flow for at least 15 minutes in order to smooth out any difference in temperature etc e Use the software to show the Reynolds number on screen e Adjust valve V2 such that the required Reynolds number is roughly attained one will need some help from someone who will give the values of the Reynolds number or one needs a display of the Reynolds number or flow rate near valve V2 e Fine tuning of the Reynolds number can be done with valve V1 To stop the flow one should take the following steps e Close valve V2 e Close valve V1 e Close valve V4 e Close valve V3 e Switch off the pumps 2 2 Measurement hardware In this section we describe the hardware that is used to perform the measurements On one hand this comprises the LDA optics and electronics and the data logging equipment needed to store the data section 2 2 1 The LDA optics is positioned relative to the pipe using a traversing mechanism see section 2 2 2 Then the miscellaneous measurements needed to characterise the flow are described section 2 2 3 and finally the connections between the different electronic components is given in section 2 2 4 The control of most components of the experimental setup as well as the data logging is per formed using the PHYDAS system Voskamp et al 1989 2 2 1 Laser Doppler Signal processing The velocity measurements are made using an LDA system of Dantec The system is based on the reference beam princip
75. w with swirl Ph D thesis Eindhoven University of Tech nology Voskamp J H Nijmwegen van F C and Wal van der A J 1989 PHYDAS een integraal systeem voor data acquisitie en besturing van fysische experimenten in dutch Ned Tijdschr v Natuurk A55 1 2 50 55 46
76. wall in wall units The latter three quantities only have non zero values when the pressure gradient is measured this can be done simultaneously with LDA measurements Nsamp is the number of samples used in the calculation of the velocity statistics In the case that only pressure data are stored the format of the files is as shown in table A 2 Here xj and x2 are the two axial positions of the pressure taps used for the measurements The last column in the file transducer indicates whether the the DP15 1 or the DP45 2 transducer has been used A 2 File format of binary file for raw data The raw data are stored in a binary file for reasons of speed and disk space In order to make the file portable all information is written in 2 byte integers unsigned short in C nat2 in PEP and 1 byte integers char in C character in PEP An integer n is stored as two nat 2 variables nat2 0 nat2 1 mo ek 2415 DIV 2416 n 2 15 MOD 2 16 A real r is stored as two nat 2 variables as follows mant float mant _exp 0 32768 expo float mant _exp 1 32768 r mant pow 2 0 expo The file starts with a header containing the data show in table A 3 Some notes are in place here The experiment code occupies 8 bytes corresponding to the space of 4 nat 2 variables For the datatype the following codes are valid they are defined in ldadec gsc which are given in table A 4 On UNIX a solution is to pass inputfile thro

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