Based on the OpenFOAM platform,we apply the k-ε turbulence model to solve the Navier-Stokes equation,use the VOF method to track the free liquid surface,establish a three-dimensional numerical water tank model to study the hydrodynamic characteristics of the rippled bed under the action of waves.The results show that the vortex in the wave period originates from the backwater slope of rippled bed and gradually rises above the crest,and then moves upstream.After going up to the maximum distance,it moves to the downstream movement under the influence of the next wave period until it is completely dissipated.The bed shear stress is concentrated in the rippled crest and back water slope,and the shear stress fluctuation frequency of upstream slope is more severe,indicating that there may be small-scale vortex,and the shedding and spreading of small vortex promote the development of large scale vortex on backwater slope.When the wave height changes,the overall trend of the bed shear force does not change significantly,and the size will change linearly.