Report summarizes the experimental and theoretical data on the vibrational response of thin-walled pipe sections to the wall pressure field applied within them by a fully developed turbulent fluid flow. The predicted responses were in good agreement with previous data obtained

Clinch, J. M.

English

NASA Technical Reports Server

December 1967
	 '.''.	 Brief 67-10518 
NASA TECH BRIEF, 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies ate available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Study Made of Thin-Walled Pipe Response to Turbulent Fluids 
A study has been conducted on the response of thin-
walled pipes to turbulent fluid flows. The objectives 
of the study were to obtain experimental data con-
cerning both the applied pressure field and the 
response it induces, and to develop an analytical 
approach for predicting the response of thin-walled 
pipes under turbulent fluid flow conditions. The re-
port summarizes both the experimental and theoreti-
cal data on the vibrational response of pipe sections 
to the wall pressure field applied within them by a 
fully-developed turbulent fluid flow. 
For the investigation, a large water flow loop was 
used together with miniature pressure transducers for 
recording wall pressure fluctuations. Statistical data 
on the wall pressure field were measured for a rigid 
thick-walled pipe. From the measurements, root mean 
square pressure levels, frequency power spectra, and 
both broadband and 1/3 octave band spacetime and 
spatial correlations of the wall pressure field were 
obtained over a range of Reynolds numbers from 
5x 105 to 2x 106. 
Using the wall pressure field data, an analytical 
method for predicting the response of pipes carrying 
turbulent fluid was developed. Based on the random 
vibration theory, the analysis assumes that the pres-
sure field is homogeneous and that the response can 
be calculated without knowledge of the mode shapes
of the many pipe resonances associated with broad-
band frequency excitation. The average pipe wall 
response can be calculated with knowledge of only 
the damping factor and the number of resonant modes 
per unit bandwidth. 
The predicted pipe wall responses were in '
 good 
agreement with data obtained by direct measurement 
at selected frequency bandwidths and several flow 
rates. 
Notes: 
1. This information should be helpful in designing 
fluid piping systems. 
2. Inquiries concerning this invention may be di-
rected to:
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B67-10518 
Patent status: 
Inquiries about obtaining rights for the commer-
cial use of this invention may be made to NASA, 
Code GP, Washington, D.C. 20546. 
Source: J. Michael Clinch

of IITRI
under contract to

Marshall Space Flight Center

(MFS- 132 1) 
Category 05 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
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Study made of thin-walled pipe response to turbulent fluids

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