水流对聚焦波特性影响的数值模拟

Numerical investigation of the current influence on the characteristics of focused waves

为了研究水流对聚焦波浪特性的影响规律,利用势流理论建立了聚焦波和水流混合作用的完全非线性数值水槽模型,在时域内利用高阶边界元方法进行模拟,并采用混合欧拉-拉格朗日方法追踪流体瞬时水面.通过实时模拟造波板运动在均匀水流中产生聚焦波浪.通过对比发现,该数学模型可以准确模拟聚焦波浪的传播变形过程,并进一步研究了水流对聚焦波的影响,包括对聚焦波浪峰值、聚焦位置和聚焦时间的影响等.

In order to investigate the influences of current on focused waves, a 2D fully nonlinear numerical wave tank model was developed for studying the interaction between focused waves and uniform water current based on the potential theory. The higher-order boundary element method （HOBEM） was used in the proposed model and the mixed Eulerian-Lagrangian approach was adopted to update the instantaneous free surface. The focused wave trains were numerically generated by a piston wavemaker on a uniform current. By contrast, the mathematical model is proved to be able to accurately simulate the deformation process of focused wave during propagation. Then the influ- ence of uniform currents on the properties of the focused waves, including maximum focused wave crest, shift of fo- calposition and focal time, were further examined.