An Investigation of Temperature Fluctuations on Bluff Bodies

Author: Gorecki, Jacek Piotr

Year: 1960

Degree: Dissertation (Ph.D.)

Advisor: Liepmann, Hans Wolfgang

Committee Member: Unknown, Unknown

Option: Aeronautics

DOI: 10.7907/KV3S-CJ64

Abstract

Temperature fluctuations and recovery temperatures on the surface of a circular cylinder (with axis normal to a subsonic compressible flow) and the field of flow about the cylinder, particularly the wake area, are investigated experimentally in range between M = 0.35, Re = 117,000 and M = 0.70, Re = 201,000.

Spectral analysis of fluctuations on body surface and other evidence indicate that formation of discrete vortex cores from the separated shear layers is initially an impulsive random process (of the generalized "shot effect" type), although the wake farther downstream from the model has a definitely periodic structure.

Impulsive formation of vortex cores can be enhanced by wind tunnel resonance or by a high turbulence level in the free stream and is accompanied by abnormal cooling of the model surface in the separated area - the mechanism of these effects is also investigated.

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