Aerodynamic drag reduction plays a vital role in the reduction of automobiles fuel consumption. Boundary layer physics and its intricate mechanisms that result in flow separation are to be understood and manipulated using active or passive devices, in order to reduce drag. Active flow control has an advantage to be effective in wide range of flow conditions and is analysed in this research. Direct Numerical Simulation (DNS) is performed for computing the flow over ahmed body, which is a simflied car geometry for research activities. Two flow control techniques, steady blowing and steady suction, are implemented for a parametric set inspired from literature. Three simulations are computed i.e., a detailed Baseline flow simulation, then a simulation with steady suction and another with steady blowing. The Reynolds number (Re) based on ahmed body (1/4th scaled) height is 1.48 *10^4. Steady suction provided a 8.3% drag reduction followed by 3.9% increase with steady blowing, specific to the parametric set considered. The major contribution from this paper is an in-depth analysis of flow physics resulting in this performance and also clearly classifying the differences using suction and blowing actuation.

Peer Reviewed