波浪潮流共同作用下长兴岛海区二维悬沙输运数值模拟研究

根据近岸地区波浪、潮流与泥沙运动的规律,把波浪运动概化为在潮周期中具有时均意义的波浪流分布场,将波浪辐射应力以及波流底部剪切应力耦合到潮流运动方程和悬沙输运方程中,建立了非结构网格下近岸波浪和潮流共同作用下的二维悬沙输运数值模型。时间离散采用欧拉向前格式,空间离散采用有限体积法的显式格式。将模型应用于矩形海湾实验和大连长兴岛附近海区悬沙冲淤过程的实际算例。结果表明:波浪对潮位影响很小,但是对近岸流速有较为明显的影响;波流共同作用对近岸泥沙浓度影响比单纯考虑潮流作用可提高40%～100%的幅度。

Numerical simulation on 2-D suspended sediment transport under waves and currents at the sea area of Changxing Island

According to the law of near-shore waves,tidal currents and sediment variation,in this paper the wave motion is approximated as the time-averaged wave flow distribution field and the wave radiation stress and wave-flow bottom shear stress are included into equation of momentum and sediment transport.And a 2-D mathematical model for suspended sediment transport under waves and tidal currents in unstructured grid has been established,in which the time dispersion is made by Euler forward schemes,and the spatial dispersion is made by explicit schemes with finite volume method.The model has been applied in a ideal experiment of the tidal inlet and the sea area near Changxing Island which located in Dalian to compute the sediment scour and deposit.The result indicates that the influence of wave on tidal level is weak,while the influence of wave on current is obvious,and introducing waves can make sediment concentration increased by 40%~100%.