| Movements of sediment in the estuarine and coastal area are complicated because of the combined effect of tidal current and waves, which is still the main topic of numerical model of sediment.Relevant research work of sediment numerical model for wave-current coexisting condition, moving boundary due to tidal waves at the tidal flat, parallel computing for hydrodynamic model is reviewed at first. Then a numerical model of sediment movement(2DST) is established by adding wave factor in the 2D tidal current module(2DTC) of COASTALTOOLs, which is based on the finite volume method. Details of the research work are as below:(1) Based on the original COASTALTOOLs model, the existing mistakes is modified, such as the formula of sediment source term, the angle of currents and waves, the logical relationship of numerical calculation, so that the model is more proper.(2) The sediment open boundary condition, bed update, the connector of wave field coupling with SWAN, the OpenMP parallel computing is added to the original procedure, which makes the two-dimensional tidal and sediment numerical model for wave-current coexisting condition more fast and reasonable.(3) In the theory aspect, the solving process of discretization of equation of continuity with submergence index is improved. And a new method to calculate moving boundary is proposed, the governing equation is solved uniformly without distinguishing wetting and drying grid in the computational domain, so that the physical quantity in the moving boundary is simulated more accurately.(4) Through numerical model of typical example, the sediment movement under different tidal and wave condition is simulated, and the sensitivity of sediment source term to velocity, wave height and wave direction is analyzed. Through numerical model of uniform bottom example, the feasibility of the new method of moving boundary is studied, the distribution of current, wave, sediment related physical quantity under different water depth is simulated. |
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