A Historical Perspective of Design Requirements for AEDC's Propulsion Wind Tunnel and von Kármán Facilities.

Author(s):  
David Hiebert ◽  
Frank Steinle
1968 ◽  
Vol 90 (1) ◽  
pp. 134-146 ◽  
Author(s):  
Y. N. Chen

This paper treats the problem of vibration and noise in tube-bank heat exchangers. The frequency of vortex shedding has been investigated by many authors, and their results have varied considerably. The author, in previous works, correlated these different data into a curve group of his own, and now proceeds to further analyze the problem. Results of experiments performed in a small wind tunnel are given, accompanied by typical graphs. Based on his findings, the author concludes with some design proposals for suppressing vibrations.


In the first part of this paper opportunity has been taken to make some adjustments in certain general formulae of previous papers, the necessity for which appeared in discussions with other workers on this subject. The general results thus amended are then applied to a general discussion of the stability problem including the effect of the trailing wake which was deliberately excluded in the previous paper. The general conclusion is that to a first approximation the wake, as usually assumed, has little or no effect on the reality of the roots of the period equation, but that it may introduce instability of the oscillations, if the centre of gravity of the element is not sufficiently far forward. During the discussion contact is made with certain partial results recently obtained by von Karman and Sears, which are shown to be particular cases of the general formulae. An Appendix is also added containing certain results on the motion of a vortex behind a moving cylinder, which were obtained to justify certain of the assumptions underlying the trail theory.


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