AN EXAMINATION OF DRIVING FORCE OF WATER SURFACE OSCCILATION AT OPEN-CHANNEL SIDE CAVITY FLOW

Abstract

It is well known that a surface oscillation is generated by installing a rectangular side-cavity structure to an open channel flow. The intensity of oscillation increases greatly as the increase of the Froude number. In addition, the type of oscillation changes easily depending on the shape of side-cavity and the width of ratio of the main channel to the depth of side-cavity. In our previous experiments, we categorized the oscillation pattern into four types. In the present study, the space-time correlation relations between the surface elevation and the velocity component at the inlet of the side-cavity is examined by the large eddy simulation that allows the water surface variation. It was found that the type of oscillation is largely divided into two types, i. e. with and without a strong depth-velocity correlation.