COMPUTATION OF FORMATION PROCESS OF DUNES BY MEANS OF NUMERICAL MODEL CONSIDERING THE EFFECT OF PRESSURE GRADIENT

Abstract

 The formation of sand waves is an important issue in river engineering, since they affect the flow and sediment transport, and their resistance to the flow changes during the formation and transition processes of dunes. In this study, a three-dimensional flow model was combined with a sediment transport model that takes into account the effect of pressure gradients near a riverbed and applied to the formation process of dunes, and the validity of the model was verified. The numerical model reasonably reproduces the formation process in which the relatively regular waves generate in the early stage change to the dunes, and the upstream dunes catch up with and merge with the downstream dunes to form large-scale dunes. In addition, the flow characteristics before and after the merge of dunes are examined from the numerical results.