EXPERIMENTAL STUDY ON THE LOCAL EROSION VELOCITY DUE TO ASYMMETRY OSCILLATORY FLOW

Burrowing bivalves such as surf clams (Pseudocardium sybillae) that inhabit open sandy beaches are an important fishery resource. The main reason for the decrease in the number of bivalves is due to high waves, and the release of bivalves from the seabed into the water is thought to be the first phase in the mortality process of bivalves. Local erosion and accumulation velocities during sand ripple formation caused by the asymmetry oscillatory flow are experimentally studied.The intensity of bed deformation speed and maximum erosion velocity due to asymmetry oscillatry flow are estimated from the results due to oscillatry flow, taking into account the effect of asymmetry on Shields number.