Experimental Study on Characteristics of Wake behind Vibrating Three-dimensional Square Prism

Abstract

This paper presents characteristics of wakes behind the vibrating three-dimensional square prism. In this study, in order to identify the instantaneous vector image corresponding to the given across-wind deflection, Particle Image Velocimetry (PIV) system is applied with synchronized laser displacement measurements.It can be noted that the distance of downstream stagnation point from the leeward wall (X_d.s.) depends on the characteristics of approaching flow such as the intensity of turbulence and the mean velocity. In the turbulent flow, the distance X_d.s. is fairly stable. On the other hand, in the uniform flow, the distance X_d.s. rapidly gets the smallest value when the vibrating prism is subject to the vortex shedding.The behavior of wake just behind the vibrating prism has been of interest. By means of synchronized measurements, it is observed that both the reverse flow and the entrainment flow are periodically generated coinciding to the vibration.