OSCILLATORY FLOW BEHAVIOR IN THE VICINITY OF RIPPLE MODELS

Abstract

A two-dimensional LDV was used to measure the flow velocity at preset grid points. By using these velocity data the vorticity at each grid point was calculated and the equivorticity lines were drawn for the sharp crest ripple as well as the round crest ripple at various phases of oscillatory flow. Then the circulation outside the vortex was evaluated. Based on the available data the temporal variation of the circulation was discussed quantitatively. Finally criteria of vortex formation were introduced and the physical meaning of these criteria was discussed.