Numerical analysis of tsunami-structure interaction using a modified MPS method

Coastal structures are regarded as an effective defense for protecting the coastal area from tsunami disasters, considering that the tsunamis cannot be predicted. Therefore, much attention should be focused on tsunami-structure interaction (TSI). We must determine dynamic characteristics of the TSI such as wave height, free-surface elevation, dynamic wave pressure, and overtopping volume, all of which are essential to the design of coastal structures. The traditional mesh-based numerical method fails to accurately model TSI, because of large deformations that cause numerical diffusion. The moving particle simulation (MPS) is a pure Lagrangian mesh-less method, which can track free-surfaces with large deformations. The original MPS suffers from serious pressure fluctuations that affect the accuracy of the simulation. We modified three aspects of the original MPS: the kernel function, the source term, and the search of free-surface particles. We verified that these changes improved the pressure stability using two benchmark problems. Then, we applied the modified MPS to simulate the TSI, using a solitary wave to model the tsunami. We quantitatively and qualitatively compared our numerical results with the experimental data. The numerical results were consistent with the experimental data, which indicates that the modified MPS can capture the essential dynamic characteristics of the TSI and reproduce the entire interaction between the tsunami and structure.