近岸波生环流的三维数值模拟研究

Three-dimensional numerical simulation of the wave-induced nearshore circulation

为研究近岸波浪破碎引起的复杂波生环流问题,本文基于三维水动力模型,引入随水深变化的辐射应力项,同时考虑波浪对水体紊动影响以及波流联合作用下的底部切应力,得到了波生流三维数值模型;模型基于非结构化网格拟合复杂的岸线变化,同时采用有限体积法进行数值离散。模拟了波浪浅化和破碎引起的斜坡地形上的垂向环流、人工岛后的平面环流以及波状地形下的裂流和沿岸流现象。结果表明:波致辐射应力的二维和深度分布不均会驱动平面和垂向的波生环流;同时与实验的比较,验证了本模式在计算近岸波生三维环流上的精确性和有效性。

In this paper,the complex wave-induced nearshore circulation caused by broken waves was studied.Based on the three-dimensional（ 3D） hydrodynamic ocean model,a 3D wave-induced current model was built by taking the depth-dependent radiation stress into current fields and considering the wave-induced turbulence and the bottom shear stress under the combined action of wave and current. Taking into consideration unstructured meshes,the model was used to fit the change of complicated shorelines,and at the same time was discretized numerically by the finite-volume method. Using the proposed model,the vertical circulation in the slope terrain induced by wave shoaling and breaking,the planar circulation after the artificial island,the rip current,and alongshore current under the wavy terrain were simulated. The results showed that the wave-induced horizontal and vertical circulation will be driven by inhomogeneous distribution of the wave-induced radiation stress along two-dimension and depth.The simulation results are compared with the experimental data to validate the accuracy and availability of the present model on simulating the 3D wave-induced nearshore circulation.