Articles summarizing results of methods and hardware survey for dynamic pressure measurement in wind tunnel and flight test

Kelly, R. D.

English

NASA Technical Reports Server

FINAL REPORT ON CONTRACT NAS 8-20179 - 
STUDY OF CROSS-CORRELATION 
SYSTEMS ANALYSES 
MAC 511-10 
R. D. Kelly 
September 1966 
MEASUREMENT ANALYSIS CORPORATION 
10960 Santa Monica Boulevard 
Loa Angelee, California 90025 
https://ntrs.nasa.gov/search.jsp?R=19660030651 2020-03-16T17:50:26+00:00Z
CONTENTS 
1. Introduction ...................................... 1 
2. Summaryof T a s k s a n d R e r ~ t s . .  ....................... 2 
3. Reconunendations for Future Activities. . . . . . . . . . . . . . . . . . . . .  3 
ii 
1. INTRODUCTION 
This report is the f ina l  management summary of the results obtained 
on NASA Contract NAS 8-20179, entitled "Study of Cross-Correlation 
Syrtems Analyses." The original contract rtarted on June 29, 1965 and 
continued through February 28, 1966. 
were  to: (1) survey commercially available hardware suitable h i  s c q ~ k -  
ing and analysing dynamic pressure data for both wind tunnel and flight 
dynamic pressure measurement programs, and (2) study the e r ro r s  
associated with practical analyeir equipment. On March 1, 1966 the 
contact wai  extended until August 31, 1966. 
extension was to assist the Unsteady Aero-Dynamics Branch in a selec- 
tion of equipment for the dynamic pressure measurement program and to 
begin an evaluation of the accuracy of the hardware procured. 
The primary goals of this contract 
The primary effort of the 
In the section that follows, the ta6k6 undertaken and the results 
obtained are described through a brief r uinmary . of the documents that 
were issued by MAC under thim contract. In the final section of the 
report, recommendations for future activities, based upon the results 
obtained under this contract, a r e  given. 
1 
2. SUMMARY OF TASKSAND R E S U L T S  
In this section the reports and then the memos issued under this 
contract a r e  summarized. 
Technical Report 8 
"Techniques and Errors  in Measuring Cross-Correlation and Cross- 
Spectrai Iiensiiy Fuaciiona, ' I  5; E. E. Kellyi L- D. Enochson. and 
L. A. Rondinelli, dated February 1966. 
This report discusses both technique8 for the measurement of 
cross-correlation and cross-spectral density b c t i o n s  and e r ro r s  
in these measurements. 
tion techniques presently in use a re  discribed. In addition, those 
techniques used in the radar and communication fields that appear 
useful for the specific application of interest (dynamic pressure 
meamrements) a r e  detailed. 
statistical uncertainity errore from the analysis of records with 
finite bandwidth and a finite duration and the hardware related 
errors.  
the entire measuring system from the transducer to the analyzer. 
Both static and dynamic phase e r rors  a re  covered. In addition, 
e r ro r s  from analyzer parameters (filter bandwidth, scan rate, 
etc. ) extraneous additive noise, finite transducer size, and 
magnetic tape recorder velocity non-uniformities a re  discussed. 
This report was published a s  NASA CR-74505. 
Analog, digital, and hybrid data reduc- 
The er ror  formulae cover both 
Particular emphasis is placed on phase e r rors  throughout 
"Survey of Dynamic Pressure Data Acquisitions and Analysis Equip- 
ment, " by R. D. Kelly and J. H. Wise, dated February, 1966. 
This report contains the results of a survey of commercially 
available dynamic pressure data acquisition and analysis equip- 
ment. Included in the rurvey a re  transducers, signal conditioners, 
2 
multiplex ryrtemr, tape recorder 8, cror r  -correlation analyserr, 
and crora -spectral denrity anzllyterr. System6 ruitable for the 
mearurement of dynamic pressures during both wind tunnel and 
during flight tert  program8 are covered. The performance capa- 
bilitier of the variour inrtrumentr a r e  compared in tabular form. 
Recommendationr a re  made on rpecific equipment for ratirfying 
both the flight tert  and wind tunnel tert reqvliraaieiitr sf +At 
Unrteady Aerodynamicr Branch. 
"Data Reduction Syrtem Requirementr - Crorr-Correlation of 
Dynamic Prer rure  Mearuremeatr from Wind Tunnel Tsrtr  of the 
4% SATURN Model," by R. D. Kelly, dated June 1966. 
Thir report dercriber the characterirticr that a r e  required in a 
crorr-correlation analyrir ryrtsm for it to be ruitable for the 
analyrir of the data obtained during wind tunnel tertr of the 
4% SATURN V model. A functional form for the crorr-  
correlation war amrumed and the sllalycer parameterr calculated. 
The analyrir characterirticr dercribed in this report a r e  time 
delay rerolution, time delay range, record length, and rampling 
pulre requirementr for A/D converrion. 
vide a guideline for the analyrir of the wind tunnel data. 
Thir report rhould pro- 
''Speciai A;D Cerr-;srsiczn Technicpe," by R. D. Kelly, dated July 1966. 
c Thir report dercriber a rpecial A/D conversion technique d t -  
able for the analyrir of l a rge  quantitier of crorr-correlation or 
crom-rpectral denrity b c t i o n r  in a rhort period of time, parti- 
cularly when very rmrll time-delay rerolution ir required in the 
correlation function analyrer or when very high frequencies are 
prerent in the crorr-rpectal analyrer. The acquirition of Parge 
3 
quantities of high frequency data in a rhort period of time dictate6 
the uee of analog tape recording. 
large quantitier of data in a rhort period of time dictate. the ure 
of a digital computer. 
permit. the convlsrricm of -log data into a digital format with 
practical cawerriaa equipment and digital tape equipment perfor- 
Converrely, the analyrir of 
The tec-re dercribed in thir report 
-8 c b r T 8 C b r b a C 8 .  fn 8 d d k - o  8 Xndikr~ic%l 'r6 L k O k  
rcherne reruhr b a method of reducing tho e r ro r r  arrochted with 
time-bare inatability of the -log tape recording. 
"Calibration and Laboratory Evaluation of the Kirrler Prer rurs  Trans- 
ducer and Charge Amplifier,'* by LTV Rerearch Center, Wertem 
Divirion, dated August 1966. 
Thir report dercriber the performance of the wind tunnel tranr- 
ducer and charge amplifier combination under laboratory and 
certain relected environmental teat. (The environmental tent. 4 
that were  performed on the unit. were vibration, temperature, 
a d  acaortic noire). Five trmrducing ryrtemr a re  evaluated. 
The performuace meaNvmentr include linearity, frequency 
reaponme, p h r e  rhift, and noire threrhold. 
TeChnk81 M8-8 
"Review of the Dynamic Prearure Mearurement Syrtam for the 
SATURN 40% Model Flight Teat Pro#ram*l by R. D. Kelly, &ted 
I4 Septsmbr 1965. 
Thir memo prerentr conclurionr and recommendrtionr on the 
two proposed ixmtrumentation ryrtenu (one by the White h n d r  
Mirrile h n g e  and the other by the Artrionicr Divirion of MSFC) 
for the flight teat of the 40% SATURN model/Little Joe boorter 
combination. 
4 
"Phaee Meaeurement Errorr  Caused by Magnetic Tape Recorderr, l 1  
by R. D. Kelly, dated 14 September 1965. 
Thir memo briefly rummariser phare errore that occur through 
the ure of analog magnetic tape recording and maker recommen- 
dation. on how to minimise there errore in practice. 
llEvaluation of Inrtrumentation Accuracy - MSFC Wind Tuanel Teato 
bvwubb=u m--A--A-.a -I. * *-"I am-- -.----- P - = m = r r h  -- C-c&er:ft by R. I). Kelly, dated 22 
February 1966. 
In thir memo, an analytical emtimation ir made of the inrtru- 
mentation errore arrociated with the data acquirition ryrtem 
ured by the Amer Rerearch Center to obtain rome wind tunnel 
data for the Unrteady Aerodynamicr Branch of Marrhall Space 
Flight Center. 
"Environmental Terting Program for the SATURN 4% Model Fluctu- 
8 t h g  Prerrure  Inrtrumentation,ll by T. D. SChOerrow, dated 18 
June 1966. 
Thio memo dercriber tertr  derigned to evaluate the performance 
of the wind tunnel data acquiritian eyrtem. Both bench-type 
performance tertr  and environmental qualification tertr  a re  
d e m c r !  
"Commercially Available Acourtic Calibratorr, 
dated 25 July 1966. 
by T. D. Shwrr~~ ,  
Thir report dercriber the remala of a rpecirl mrvey of com- 
mercirlly available high-le-1, high-f reqacrsrcy, portable acop8tic 
calibrstorr. 
roitable crlibrstorr were caanmrrcidly s v a h b l e  for in-phce high 
frequency scourtic c8librstion of the 4% SATURN V model inrtru- 
mentation in the wind tunnel. 
The purpors of thir mrvey w 8 e  to determine if m y  
5 
"Wind Tunnel Instrumentation Evaluation Tests, I '  by R. D. Kelly 
and T. D. Schoessow, dated 12 August 1966. 
This memo deocribes a set of tests designed to evaluate the 
performance characteristics of the wind tunnel data acquieition 
system while installed at the test facility. 
equipment necessary for these evaluation tests a r e  listed. 
In addition, teat 
"Evaiuation 0; &e A n ; i i y ~ i s  q ~ + z , e ~ t  Accl;racg - ~ ~ & ~ . - ~ ~ l l  C . y ~ s e  - 
Spectral Analog System," by P. E. Rentz, dated 31 August 1966. 
In this report, an analytical estimation is made of the accuracy 
of the cross-spectral density rystem used by McDonnel Aircraft 
Corporation to analyze some wind tunnel data for the Unrteady Aero- 
dynamic8 Branch of MSFC. 
"Comments on Pressure Tranaducer Evaluation, l a  by T. D. Schoessow, 
dated 31 August 1966. 
Thio memo contains a description of the results obtained by the LTV 
Research Center during their calibration and environmental evalua- 
tion of five dynamic pressure transducers and their associated 
charge amplifiero. 
6 
3. RECOMMENDATIONS FOR FUTURE ACTIVITIES 
Based on the experience gained during this contract, the following 
tasks a re  recommended to the Unsteady Aerodynamics Branch for imple- 
mentation: 
1. Analyze the errors  associated with the wind tunnel instrumentation. 
Since the neceoaary b*c to G Z t z i d r =  %!e a,l?plftizdei phage: and 
noise threshold level performance of the entire wind tunnel mea- 
surement system has been collected, it is strongly recommended 
that this data be analyzed and the error  associated with this mea- 
surement system be determined. 
data collected should provide some correction factors for exten- 
sion of the overall accuracy of this instrumentation system 
In addition, it is felt that the 
2. Complete the tape dynamic phase error  measurements. It is 
recommended that experiments be performed to evaluate the 
errore occurring from non-uniform velocity of analog magnetic 
tape recorders. 
under the contract and the experiments a re  required to check on 
the validity of the analytical model. 
3. Investigate the feasibility of the special A /D conversion technique. 
It is recommended that the rpecial A/D conversion technique 
described in Section 2 be checked by assembling a breadboard 
model of an operating system. 
permit the analyris of greater quantities of data per analysis  
dollar than ir presently posrible and indeed may well be the only 
practical method to obtain the time delay resoluation and accuracy 
required. 
A n  analytical model for this error  was developed 
If the system is feasible it will 
7 
4. Assist the Unsteady Aerodynamics Branch in the analysis of the 
data obtained during the wind tunnel tests. 
5. Investigate practical techniques for performing phase calibration 
of small microphones at high frequencies and high levels. 
6. Evaluate the performance of the transducer systems after the 
wind tunnel tests a r e  completed in order to determine any 
permanent shifts that m a y  have occurred in tile pCifsr*xznce cf 
these instruments due to the wind tunnel environment 
8 


Study of cross-correlation systems analyses Final report, Jun. 29, 1965 - Aug. 31, 1966

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server