Bluff-Body Flow Control by Aerodynamic Tripping

Drag reduction and lift enhancement for a circular cylinder is achieved here simultaneously by steady rotation and rotary oscillation of the cylinder. Rotary oscillation provides the necessary aerodynamic tripping of the laminar boundary layer initiated on the windward side of the cylinder and thus reducing the drag. While the steady rotation provides the high lift via Magnus-Robins effect. Results are presented here for a Reynold’s number (based on cylinder diameter and oncoming flow velocity) of 1000. Proper orthogonal decomposition (POD) of the vorticity data obtained from the solution of Navier-Stokes equation helps in identifying the physical mechanism(s) involved in the flow.