Numerical Model For Coastal Wave And Near-shore Wave-induced Current In Quad-tree Grid

Coastal zone has most closely relationship with human life and production. At the same time,Near-shore wave and current is most active in this zone. Near-shore wave and current are key hydrodynamic factors in water environment, and have important effects on coastal exploitation and construction engineering. In this paper, The numerical models for coastal water wave and wave induced current in quad-tree grid are developed.First of all, the coastal wave numerical model is developed based on elliptic mild slope equation in the quad-tree grid. The model is discretized with finite volume method and solved with GPBiCG (m, n) algorithm. The model is validated by modeling the wave transformation in physical model experiment, and then it is applied to modeling the wave propagation in the Acapulco Bay. The numerical results show that the model is reliable and efficient in modeling coastal wave propagation.Secondly, the2D palne numerical model for near-shore wave-induced current is developed in the same quad-tree grid. In the model, the wave radiation stress is directly calculated from the wave potential in elliptic mild slope equation and the wave reflection, refraction and diffraction effect are consided in. The model is applied to modeling the wave-induced current in the offshore artificial island and San Francisco Ocean Beach, and the numerical results are consistent with measured results. The numerical results show that the model is reliable and efficient in modeling near-shore wave-induced current.The numerical models for coastal wave and near-shore wave-induced current in quad-tree grid system can refine the grid size in accordance with the water wave lengths, and has good adaptability with the complex topography. The model is efficient in computation time and storage space, and there is no complicated cross-term in the process of model discretization. It is shown by numerical results that the model is effective and efficient in modeling coastal wave and wave-induced current, and can be an effective tool for coastal engineering and research.