Study on Wake of a Yawed Square Cylinder Using Particle Image Velocimetry

Abstract

The wake of a yawed square cylinder undergoing steady flow was examined by employing particle image velocimetry (PIV) technique. The present study is concerned with the independence principle (IP) for a square cylinder by examining the effect of the yaw angle (α) on the velocity signals and the vortical structures. The normalized Strouhal number indicates that the IP is no longer applicable when α reaches 45°. At α = 45°, the distorted vorticity contour and the reduction of the vorticity strength, imply the significant effect of the yaw angle. The generation of the axial flow from the base of the yawed cylinder makes the communication between the shear layers more difficult and hence weakens the vortex shedding process, which manifests a strong three-dimensionality of the wake, resulting in the invalidity of the IP for α = 45°.