Hill, Murray K. and Zukoski, Edward E. (1972) Behavior of Spherical Particles at Low Reynolds Numbers in a Fluctuating Translational Flow. Preliminary Experiments. Aerospace Research Laboratories, ARL 72-0017. Air Force Systems Command, United States Air Force , Wright-Patterson Air Force Base, Ohio. http://resolver.caltech.edu/CaltechAUTHORS:20101220-154423061
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The behavior of small spheres in non-steady translational flow has been studied experimentally' for values of Reynolds nunber from 0 to 3000. The aim of the work was to improve our quantitative understanding of particle transport in turbulent gaseous media, a process of extreme importance in powerplants and energy transfer mechanisms. Particles, subjected to strong sinusoidal oscillations parallel to the direction of steady translation, were found to have changes in average drag coefficient depending upon their translational Reynolds number, the frequency and amplitude of the oscillations. When the Reynolds number based on the sphere diameter was les s than 200, the synunetric translational oscillation had negligible effect on the aver age particle dr ago For Reynolds numbers exceeding 300, the effective drag coefficient was significantly increased in a particular frequency range. For example, an increase in drag coefficient of 25 per cent was observed at a Reynolds nwnber of 3000 when the amplitude of the oscillation was 2 per cent of the sphere diazneter and the disturbance frequency was approximately the Strouhal frequency. The occurrence of the maximum effect at frequencies between one and two times the Stroubal frequency strongly suggests non-linear interaction between wake vortex shedding and the oscillation in translational motions. Flow visualization studies support this suggestion.
|Item Type:||Report or Paper (Technical Report)|
|Additional Information:||© 1972. CONTRACT F33615-69-C-1069 ; PROJECT 7116. Descriptive Note: Rept. no. 1 (Final), 1 Sep 1970-31 Aug 1971. Approved for public release; distribution unlimited. This report covers that portion of the work performed under Contract F33615-69-C-1069 from 1 September 1970 through 31 August 1971. The project engineer monitoring this contract was Mr. S. H. Hasinger (LE). Energy Conversion Research Laboratory, Aerospace Research Laboratories. Technical contributions to this work were made by Mr. Murray K. Hill, Dr. Edward E. Zukoski, Dr. W. Duncan Rannie, and the Principal Investigator, Dr. Frank E. Marble. We are particularly indebted to Dr. H. von Ohain, Chief Scientist, A. R. L., and to Mr. S. H. Hasinger, Energy Conversion Research Laboratory, for their many technical discussions which were of singular importance in choosing areas of emphasis. Another report published under above contract is ARL 72-0018 "An Experimental Investigation of Particle Motion in a Liquid Fluidized Bed" by Charles A. Hillus.|
|Group:||Guggenheim Jet Propulsion Center|
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|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||12 Jan 2011 18:39|
|Last Modified:||26 Dec 2012 12:47|
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