Drag reduction by flow separation control on a car after body

Abstract

International audienceNew development constraints prompted by new pollutant emissions and fuel consumption standards (Corporate Average Economy Fuel) require that automobile manufacturers develop new flow control devices capable of reducing the aerodynamic drag of motor vehicles. The solutions envisaged must have a negligible impact on the vehicle geometry. In this context, flow control by continuous suction is seen as a promising alternative. The control configurations identified during a previous 2D numerical analysis are adapted for this purpose and are tested on a 3D geometry. A local suction system located on the upper part of the rear window is capable of eliminating the rear window separation on simplified fastback car geometry. Aerodynamic drag reductions close to 17% have been obtained

Drag reduction of a car model by linear genetic programming control

“…Most of the studies are dedicated to manipulate the wake by forcing the separated shear layer. These include the application of steady blowing or suction of air flow (Rouméas et al 2009;Aubrun et al 2011) or unsteady synthetic or pulsed jets (Glezer et al 2005;Rouméas et al 2009;Park et al 2013;Joseph et al 2013;Oxlade et al 2015;Seifert et al 2015) on the separation trailing edges. AFC can be combined with passive deflected surfaces to gain additional base pressure recovery by enhancing the shear layer deflection (Englar 2001(Englar , 2004Schmidt et al 2015;Barros et al 2016b).…”

Influence of Short Rear End Tapers on the Unsteady Base Pressure of a Simplified Ground Vehicle

“…Or alternatively using active flow control techniques, such as suction [7], blowing [8] and oscillating suction and blowing [9]. The results from such active systems suggest they can be effective in manipulating the wake structure with minimal impact on the external shape of the vehicle, but the reduction in drag is often outweighed by the increase in the vehicle mass and the energy input required to operate them.…”

Influence of Short Rear End tapers on the Base Pressure of a Simplified Vehicle.

“…This can be achieved through passive optimization, for example geometry changes, vortex generators, flaps, and surface roughness, or using active control, for example, suction, blowing, oscillated suction and blowing, moveable vortex generators or flaps [2][3][4][5][6][7][8][9][10][11]. Active flow control is an attractive option because of the potential freedom it allows for vehicle styling as all that is required externally is the jet orifices.…”