Flow over a cylinder subjected to combined translational and rotational oscillations

Abstract

The experimental research reported here employs particle image velocimetry to extend the study of Nazarinia et al. (2009a), recording detailed vorticity fields in the near-wake of a circular cylinder undergoing combined translational and rotational oscillatory motions. The focus of the present study is to examine the effect of the ratio between the cross-stream translational and rotational velocities and frequencies on the synchronization of the near- wake structures for multiple phase differences between the two motions. The frequencies are fixed close to that of the natural frequency of vortex shedding. The results are presented for a fixed amplitude of rotational oscillation of 1 rad and a range of ratios between the translational and rotational velocities ðVRÞ 1⁄4 1⁄20:25,0:5,1:0,1:5