COMPUTATIONS OF THREE-DIMENSIONAL ANTIDUNES IN RIVERS

Abstract

 Despite the great success of the research of bedform morphodynamics, the three-dimensionality of the bedforms have still not been understood deeply. In this study, we perform numerical simulations of three-dimensional (3D) river antidunes using a combined model of a Boussinesq model, which is a depth-integrated hydrodynamic model with the non-hydrostatic effects, and a non-equilibrium bedload transport model. The model performance is tested with the experimental results of 3D antidunes. The results show that the model reasonably calculates the formation and development of 3D antidunes and subsequent formation of standing water surface waves. In addition, the results show a coexistence of the two different bedforms, namely, free bars and 3D antidunes. Some limitations of the model are shown, namely, the model can not reproduce the downstream-migrating 3D antidunes.