Experiment Research on Geometry and Evolution Characteristics of Sand Wave Bedforms Generated by Waves and Currents

Abstract

Sand waves generated under waves and wave-current have been investigated experimentally in a wave flume. The evolution of bedforms were measured by a Trasonic Terrain automatic Measurement and analysis System (TTMS). With the data measured, the configuration of the bed was analysed. With long time wave action, a large-scale bedforms as sand waves can be formed and many ripples superimposed upon them. Ripples with 2D or 3D patterns can be formed at different locations. The growth rate of sand waves was increased at the beginning and then decreased with the increase of the time. Moreover, it has been found that the sand wave features as sand wave length and height have relationship with hydrodynamics. In general, the sand wave height increases with the increasing of wave height and residual current respectively. The sand wave length increases with the increase of residual current and decrease of wave height. The sand wave growth rate increases with the increase of the hydrodynamic conditions.