Experimental and computational studies of active flow control on a model truck-trailer

¹ Division of Fluid Dynamics, Department of Applied Mechanics, Chalmers University of Technology SE-412 96 Göteborg, Sweden
² Dept. of Mech. and Aerospace Engineering, Shiraz University of Technology Shiraz, Iran

^* Corresponding author, email address: mohammad.el-alti@chalmers.se

Abstract

Active flow control is probably the most challenging research area in vehicle aerodynamics. Being able to manipulate a flow field in order to achieve desired results beneficial to engineering is the only way to meet today’s demands for competitive and efficient solutions in the automotive industry. The current work studies the flow control on a semi detailed model truck by using detached-eddy simulations and wind tunnel experiments aiming at reducing the aerodynamic drag. This study combines both passive and active flow control applied on the rear end of the trailer. An indigenous fluidic actuator (loudspeaker in cavity with slots) is used as a synthetic jet in the experiment. Both experiments and computations demonstrate that the active flow control works successfully and results in flow reattachment to the flaps. The numerical simulations show that the drag coefficient, C_D decreased by 3.9% when AFC was activated compared to the baseline case without flaps. The corresponding decrease when AFC was deactivated (with flaps) was only 0.7%. The experimental results show a decrease of C_D by 3.1% for the case with activated AFC compared to the baseline case. When AFC was deactivated the corresponding decrease in C_D was 1.8%. A detailed flow analysis made in computations and experiments is used to explain these results.