Modeling of suspended sediment transport with waveinduced longshore current in Huanghe (Yellow) River Delta

A three-dimensional suspended sediment model (SED) developed by the present authors is coupled with the combinatorial model of COHERENS (Luyten et al., 1999) (the three-dimensional coupled hydrodynamical-ecological model for Regional and Shelf Seas) and SWAN (Holthuijsen et al., 2004) (the third generation wave model). SWAN is regarded as a subroutine of COHERENS and gets time-and space-varying current velocity and surface elevation from COHERENS. COHERENS gets time-and space-varying wave relevant parameters provided by SWAN. Effects of wave on current are applied in bottom shear stress, wave-induced depth-dependent radiation stress and surface drag coefficient calculation. At the same time, the damping function of suspended sediment on turbulence is introduced into COHERENS. So the sediment model SED has feedback on circulation model COHERENS. The SED obtains current associated parameters from COHERENS. Then a coupled hydrodynamic-sediment model COHERENS-SED being able to account for interaction between wave and current is obtained. COHERENS-SED is adopted to simulate three-dimensional suspended sediment transport in the Huanghe River delta. In terms of simulation results, there is obvious difference between top and bottom layer of wave-induced longshore current. The values of time series of sediment concentration gotten by COHERENS-SED have, generally, an accepted agreement extent with measurement. Significant wave heights and wave periods obtained by COHERENS-SED show that wave simulation case with current's effect can give better agreement extent with measurement than case without current's effect. In the meantime, suspended sediment concentration distributing rule obtained by COHERENS-SED is similar to former researches and measurement.