Analysis and control of the nearwake flow over a squareback geometry.pdf

Available online at Computers Fluids 38 (2009) 60–70 /locate/compfluid Analysis and control of the near-wake flow over a square-back geometry ´ a ´ a b,* Mathieu Roumeas , Patrick Gillieron , Azeddine Kourta a ´ ´ Renault, Direction de la Recherche, Groupe ‘‘Mecanique des Fluides Aerodynamique” 1, Avenue du Golf 78288 Guyancourt cedex, France b ´ ´ Institut de Mecanique des Fluides de Toulouse, Groupe EMT2, Allee du Professeur Camille Soula, 31400 Toulouse, France Received 5 July 2007; received in revised form 20 December 2007; accepted 6 January 2008 Available online 10 March 2008 Abstract A 3D numerical simulation, based on the Lattice Boltzmann method is carried out on the near-wake flow behind a generic square- back blunt body to analyze and establish a method to control the near-wake flow. The flow topology is described by the velocity and the pressure fields. The influence of the wake vortices on the aerodynamic drag is clarified and quantified. In order to reduce this drag, an active open-loop flow control is applied by continuous blowing devices distributed around the base periphery. The blowing effect on the behind body flow is a reduction of the wake section and of the total pressure loss in the wake and an increase of the static pressure on the base of the square body. This co