Experimental investigation on sand bed scour by an oblique planar water jet at varying impinging angles

This study aims to investigate the effects of impinging angle of a planar water jet on the scour hole profiles and flow structure in the scour hole. Based on image recording and Particle Image Velocimetry (PIV) technology, the scour of the oblique planar impinging jet on erodible sand bed is investigated at different impinging angles over the range of 20 degrees <= theta <= 80 degrees. Time evolution of the scour hole profile was recorded using a video camera, and the flow fields in the scour hole at equilibrium state were measured using PIV. The results show that the normalized maximum dynamic erosion depth epsilon(m infinity)/h is a function of erosion parameter E = F-0 root h/B. The offset of impinging point on the sand bed from the geometric center is found to decrease with the increase in impinging angle. In addition, the jet width is larger at theta = 30 degrees and 80 degrees than that at theta = 50 degrees for the same value of streamline-wise distance l/B. The present study could give some reference for engineering applications.