黏性数值波浪水槽动边界造波技术研究

Moving-boundary Wavemaker in a Viscous Numerical Wave Flume

模仿实验室推板造波技术,在黏性数值波浪水槽中构建了造波动边界,实现了一阶线性波、二阶斯托克斯波和孤立波的数值模拟,数值波形与理论波形吻合良好,验证了这一方法的有效性.将海绵层消浪技术与辐射边界条件结合吸收透射波能,有效减小了水槽的二次反射效应.不同水深二阶斯托克斯波的模拟结果表明,斯托克斯波理论不适用于浅水情况.提出基于四阶Runge-Kutta法直接求取浅水孤立波速度时程的思路,较传统算法更为便捷.

This article integrates a rigid moving boundary into a viscous RANS-VOF wave flume to imitate the behaviors of piston-type wavemakers commonly used in physical models of coastal engineering.Three waveforms,including first-order linear wave,second-order stokes wave,and solitary wave,were generated in the viscous wave flume.Good agreement between numerical and theoretical surface elevations validates the novel technology.Wave-absorbing sponge layer based on the idea of artificial attenuation was added in front of the outflow boundary to absorb wave energy and therefore mitigate the effect of secondary reflection combined with radiation boundary condition.The simulation of second-order stokes waves in different water depths demonstrates that the stokes wave theory is not suitable for shallow water.The Fourth-order Runge-Kutta algorithm is introduced to directly solve the time process of solitary wave velocity,which is more convenient than the traditional algorithm.