ACTIVE FLOW CONTROL SCHEMES FOR BLUFF BODY DRAG REDUCTION

Numerical simulation experiments on vortex shedding and corresponding drag coefficients from a two-dimensional bluff body are perfornied over a range of Reynolds numbers from one to four million. Active control is implemented on the body via velocity boundary conditions in the form of blowing and suction jets. These controls range in velocity from half to double the free-stream inlet velocity. An overall drag coefficient reduction in excess of 75% is observed for maximum power input to the actuators. In addition, a trend of increasing Strouhal number for each successive increase in actuator power (and corresponding reduction in drag) is noted. Important physical mechanisms involving near-body wake flow are analyzed to determine optimal wake flow pattern and corresponding control schemes.