The Vortex Formation Process Behind a Rotationally Oscillating Circular Cylinder

摘要

The effects of rotary oscillation on the separated shear layer and the vortex formation process behind a circular cylinder were investigated using hot-wire anemometry and smoke flow visualization. The results show that for a forced oscillated cylinder, depending on the oscillation frequency and amplitude, (ⅰ) the shear-layer instability was promoted, (ⅱ) the interaction between shear-layer vortices and the Karman vortex could be greatly affected, and (ⅲ) the Karman wake synchronized with the cylinder motion. It is anticipated that the rotary oscillation could provide a potential means for the control of the vortex formation process.