NUMERICAL ANALYSIS OF STEADY BLOWING BASED ACTIVE FLOW CONTROL FOR FLOW OVER AHMED BODY

A numerical study is conducted to investigate fluidic actuation with steady injection for active flow control and drag reduction in an Ahmed body. Numerical results are obtained for the unsteady three-dimensional Navier Stokes equations for both baseline as well as steady injection cases. This study examines the use of active flow control devices at the rear of the 25-deg Ahmed model to reduce drag by controlling an unsteady wake. The present work demonstrates that URANS model with grid refinement at critical locations can accurately describe the aerodynamics around the bluff body with computational time of several days compared to several weeks with traditional LES simulations. In order to modify the wake and reduce the pressure drag, active flow control technique using steady blowing was applied through a narrow slit along all rear edges of the model. The effect of inlet velocity for the baseline simulations was analyzed. Computed Results showed AFC achieves significant reduction in the drag coefficient (C-d) values over the baseline simulations.