海堤坡角变化对海啸波传播过程影响数值分析

Numerical analysis of influence induced by change of seawall slope angle on tsunami wave propagation process

针对近岸海域极端海况的防灾减灾问题,准确模拟追踪海啸波传播过程,再现液面局部射流、崩破波等波面湍动现象。建立SPH数值水槽,边界条件基于固壁粒子法,减少海堤坡角改变对计算域精度的影响,讨论粒子间距设置对模拟精度的影响。模拟7种不同海堤坡角下波浪的爬高与衰减情况,讨论了海堤坡角变化对消波系数的影响。当粒子间距设置为0.002 m时,模型能准确地捕捉海啸波的强非线性现象。随着海堤坡角增大,海啸波峰值爬升率增大,波浪越堤后因崩破波的产生,波能衰减进一步加剧。当坡角较小时,消波系数随坡角的增大提升明显,而后趋于缓慢增长。

Aimming at the disaster prevention and alleviation issues of extreme sea conditions,the large tsunami wave propagation is simulated accurately,and the wavefront turbulence phenomenon such as partial jet and collapse wave is reproduced.A SPH numerical model is established with the solid wall particle boundary condition in order to reduce the influence on calculation accuracy.Impact of particle spacing setting on simulation accuracy is also discussed.Four different breakwater slope angles are analyzed under the impact of wave run-up and decay to verify the boundary condition’s applicability.The liquid surface change can be accurately captured when the model’s particle spacing is set to 0.002 m,the strong nonlinear phenomenon is reproduced during the propagation process.With the increase of slope angles,the peak climbing rate of the tsunami wave increases.The spilling breaker phenomenon is caused by the wave overtopping,which further aggravates the wave energy attenuation.When the slope angle is small,the wave-splitting coefficient increases with the raise of the slope angle,then tends to increase slowly.