ACTIVE CONTROL OF OSCILLATORY LIFT FORCES ON A CIRCULAR CYLINDER

Abstract v peak velocity of blowing/suction (experiment) The results of a computational and experimental 2, y coordinate system, centered on cylinder axis, z study of feedback control of Karman vortex shedding aligned with Uo, behind a circular cylinder are presented. The experi- z, vertical velocity sensor location ments were performed in a nominally two dimensional o feedback gain flow around a 12.7mm cylinder at Reynolds numbers I / kinematic viscosity up to 10,000. The computations utilized the two- P fluid density dimensional Navier-Stokes equations at Reynolds num- 0 azimuthal angle bers up to 100. In both experimental and numerical r time (prior to t) studies blowing and suction slots were used to con-plete suppression of vortex shedding is achieved up to a Reynolds number Re = 80 (about 70 % above the onset Many flows of engineering interest (e.g. separating Reynolds number for vortex shedding). In the exper- flows) produce the phenomena of vortex shedding and imental study using the fluctuating lift force as feed- the associated structural response. Applications in