PROBABILITY OF EXCEEDING THE CRITICAL SHEAR STRESS FOR SAND MOTION IN SPECIFIC WAVE AND CURRENT CONDITIONS

Pierre-Yves Henry, Alf Tørum, Øivind Artsen, Dag Myrhaug, Muk Chen Ong

Abstract


This study is focusing on the threshold of sand motion under random waves combined with a following current. The analysis is based on some flume experiments realized over a natural sand bed for different flow conditions (waves and currents). The main result comes as a map of the probability to exceed the threshold of sand motion, as a function of a wave and a current mobility parameter. These observations are compared to methods predicting the bed shear stress using an equivalent monochromatic wave, and links between the probability of exceeding the critical shear stress for initiation of sand motion and the calculated maximum bed shear stress are found.

Keywords


threshold of motion; random waves; critical shear stress

References


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