CONTROL OF THE WAKE BEHIND A CIRCULAR CYLINDER AT LOW REYNOLDS NUMBER

摘要

Based on the mechanism of vortex street formation owing to the instability of shear layer, some methods for controlling the wake behind a circular cylinder have been developed. The control cylinder is effective to suppress vortex street at Re number less than 200; the split plate is available for any Re number within subcri-tical region. Depending on frequency and position, acoustic exici-tations can promote free shear layers to form large-scale vortex structures, or reduce fluctuation in the shear layer, or force the separated shear layers to reattach.