Local Scour Caused by Submerged Square Jets under Model Ice Cover

An experimental study was carried out to understand the local scour process of noncohesive sand beds caused by submerged three-dimensional square jets under model ice covered conditions. The characteristics of asymptotic scour have been investigated by varying the tailwater depth, the densimetric Froude number, the grain size of the bed material, and three different types of water surface conditions (open-water flow, smooth ice covered flow, and rough ice covered flow). Results show that the local scour process under covered conditions is different from that under open water, especially at lower tailwater depths. Further, for the range of test conditions, the effect of the ice cover is reduced when the bed is composed of finer sand particles or when the densimetric Froude number is small.