Study of the wake flow around a circular cylinder

This experimental study investigated the wake flow around an elastically supported circular cylinder. In this study, the Reynolds numbers are varied in the region of 1.4×104≤ Re ≤3.2×104. Under these conditions, we have captured the process of the wake mechanism and the moving path of the vortex by measuring the velocity at each position in the wake around the cylinder. Further, these facts from the wind tunnel test are proved by a flow visualization test through a water channel. From the result, we have arrived at the following conclusions: i) The process (formation→growth→collapse) of vortex is observed in the wake around the cylinder, ii) The vortex efflux angle is approximately 16°-17° under the experimental conditions. These angles have no relationship with the velocity change and the existence of flow-induced vibrations of the cylinder, and iii) The moving path of the vortex center is obtained by spectrum analysis of the fluctuating velocity behind the cylinder. These are confirmed by conducting visualization tests. © 2015 The Korean Society of Mechanical Engineers.