A Numerical Study of the Response of the Laminar Unsteady Separated Flow about a Circular Cylinder to Changes of Boundary Conditions

Abstract

An extensive investigation of the effective possibilities of controlling the laminar unsteady separated flow about a circular cylinder is made by way of the numerical simulation on the basis of the unsteady Navier-Stokes equations. The objectives of flow control are aimed at the reduction of flow resistance and the alleviation of the fluctuating normal force. According to the present inestigations, it is apparent that in the application of the control measures attention should be paid to the different aspects of their consequences. A control measure that reduces the flow resistance may however aggravate the fluctuation of normal forces and vice versa. The optimal control can be achieved through local tangential wall motion with velocities of a fictitious potential flow.