Numerical Study of Wave Induced Seabed Response with Sand Ripples

The numerical research existing almost treats the seabed as if it were a flat foundation, ignoring the influence of morphological differences on wave-induced seabed response. In the present study, the wave induced sand ripples terrain and the seabed response beneath are investigated. A 2D hybrid model incorporating Reynolds-averaged Navier–Stokes (RANS) equations, sediment transport equation, morphological theory, and Biot’s pore elastic theory is presented in this study for wave propagation, morphological evolution, and dynamic response of seabed. The results of the experimental analysis and the numerical simulation showed good agreement. Numerical results indicate that the magnitude of pore pressure of seabed under wave crest increases. Simultaneously, the magnitude of effective stress and displacement of soil decreases, considering the ripples terrain. The morphological changes lead to an evident redistribution of the effective stress, causing a local concentration of soil stress below the sand wave trough. Moreover, the results also reveal that compared to flat seabed, the pore pressure on seabed surface fluctuates intensely, corresponding to the profile of sand ripples. As the distance from the soil surface increases, the fluctuating phenomenon vanishes.