Title: Drag reduction by pulsed jets on strongly unstructured wake: towards the square back control

Authors: E. Bideaux, P. Bobillier, E. Fournier, P. Gillieron, M. El Hajem, J.Y. Champagne, P. Gilotte, A. Kourta

Addresses: Laboratoire AMPERE (UMR 5005), Institut National de Sciences Appliquees de Lyon, 25 Avenue Jean Capelle, 69621, Villeurbanne, France. ' RENAULT, Direction de la Recherche, des Etudes Avancees et Materiaux, 1 Avenue du Golf, 78288, Guyancourt, France. ' RENAULT, Direction de la Recherche, des Etudes Avancees et Materiaux, 1 Avenue du Golf, 78288, Guyancourt, France. ' RENAULT, Direction de la Recherche, des Etudes Avancees et Materiaux, 1 Avenue du Golf, 78288, Guyancourt, France. ' Laboratoire de Mecanique des Fluides et d'Acoustique (UMR 5509), Institut National de Sciences Appliquees de Lyon (INSA Lyon), 27 Avenue Jean Capelle, 69621, Villeurbanne, France. ' Laboratoire de Mecanique des Fluides et d'Acoustique (UMR 5509), Institut National de Sciences Appliquees de Lyon (INSA Lyon), 27 Avenue Jean Capelle, 69621, Villeurbanne, France. ' Plastic Omnium Auto Exterieur Services (POAES), Parc Industriel de la Plaine de l'Ain, 01150 Sainte-Julie, France. ' Institut Prisme, Polytech'Orleans, 8 rue Leonard de Vinci, 45072, Orleans Cedex 2, France

Abstract: Experimental studies have been performed in a wind tunnel in order to control the flow separation on rear window of a generic vehicle shape (the Ahmed body with a scale of 0.7 and a slope angle of 35 degrees). The rear part of the geometry has been modified by replacing the sharp edge between roof and rear window by smooth curved surfaces. This model is equipped at the end of the roof with a strip of pulsed jets in order to control the flow with a velocity of 30 m.s⁻¹. A 20% drag reduction has been obtained with a pulsed frequency at 500 Hz and a momentum coefficient C_µ = 2.75 10⁻³. This result confirms the interest in using pulsed jets in order to reduce aerodynamic drag and pollutant emission.

Keywords: flow control; Ahmed body; pulsed jets; solenoid valve; drag reduction; unstructured wake; square back control; flow separation; rear windows; aerodynamics; pollutant emission; vehicle emissions; road vehicles.

DOI: 10.1504/IJAD.2011.038846

International Journal of Aerodynamics, 2011 Vol.1 No.3/4, pp.282 - 298

Published online: 28 Feb 2015 *

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