Numerical Simulation Of Run-up Of Double Solitary Waves

As one of the marine natural devastating disasters, tsunami is mainly caused by strong earthquakes undersea, alien meteorite impact and the submarine nuclear test. General tsunami can be caused the intense vertical movement in the deep sea. The wave heights of tsunami in the deep ocean are small, but the energy of the wave concentrate and the wave travels fast. When the tsunami waves approach inshore, due to shoaling effects, wave heights increased sharply, which make the water in the bay and harbor produces strong fluctuations or oscillations, with the waves washed up on the land, flooding the shore, destroying buildings, causing a serious disaster.The run-up of tsunami waves on beaches is the main way to cause inundation on land.A two-dimensional numerical flume is established based on the mathematical model of the incompressible, viscous flows with the free surface. The governing equations are the Reynolds averaged N-S equation and the conservation equations of the Volume of Fluid function. The modified Goring approach and the moving boundary technique are used to implement the movement of the paddle of waver maker and generation of the double solitary waves with different distance between two crests. First of all, it is found that the waves which are generated by the modified wave generation approach is in good agreement with the target waveform of a solitary wave. The several computed maximum run-up of single solitary wave on a vertical wall is consistent with the analytical solution of analytical solution and the experimental data available. The results of numerical simulation of run-up of the double solitary waves on vertical wall show that the computed results are consistent with the experimental data, and the numerical simulation worked stably. The numerical simulation results are basically consistent with the experiment results.In a certain topographic condition, the tsunami wave in the offshore propagation process is likely to evolve into a series of solitary waves. In order to understand the effects of multiple solitary wave train on coastal structures, the runup of double solitary waves on a slope or a vertical wall are simulated numerically in a numerical wave flume.The numerical analysis of single solitary wave run-up against a vertical wall is carried out to validate the numerical wave flume. For the double solitary with the same wave height, the changes of the velocity field and energy are obtained and analyzed. It turns out that, for the case of the double solitary wave with the same height, compared with the run-up amplification coefficient of the first solitary, the second ones is small. There are three peaks in the time series of the total potential energy of the wave field during the period of the run-up of the double solitary waves. At the same time, when the slope angle is small, kinetic energy of one in the double solitary waves turn into potential energy is completely before the wave climb to the highest point of the slope. If the slope angle increases to the straight wall, kinetic energy of one in the double solitary waves turn into potential energy and the wave climb to the highest point of a slope in the same a moment.