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Article Dans Une Revue Experiments in Fluids Année : 2013

Experimental characterization of flow unsteadiness in the centerline plane of an Ahmed body rear slant

Adrien Thacker
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Sandrine Aubrun
Annie Leroy
Philippe Devinant
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Résumé

This study presents results of an experimental analysis of the unsteady features of the flow around the rear part of an Ahmed body with rear slant angle of 25o. This analysis focuses on the 3D separated and reattaching zone that develops on the rear slanted surface and brings new information, improving the understanding of the flow unsteadiness. Flow investigations are performed using PIV, hot wire anenometry and unsteady flush mounted pressure transducers in the plane of symmetry above the rear slanted surface. Spectral analysis and Proper Orthogonal Decomposition of the output signals show the emergence of low frequency unsteadiness and high frequencies activities. Characteristic time scales of both instabilities are provided and the physical effect of the low frequency unsteadiness is related to a flapping motion of the separated shear layer, while the high frequency activity is associated to a large scale vortex emission. The results focus in the centerline plane of the rear slant and more specifically demonstrate relevant similarities with the unsteady mechanisms of 2D recirculated flow.

Dates et versions

hal-00836402 , version 1 (20-06-2013)

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Citer

Adrien Thacker, Sandrine Aubrun, Annie Leroy, Philippe Devinant. Experimental characterization of flow unsteadiness in the centerline plane of an Ahmed body rear slant. Experiments in Fluids, 2013, 54, pp.1479. ⟨10.1007/s00348-013-1479-5⟩. ⟨hal-00836402⟩
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