High Grid Resolution and Parallelized Tsunami Simulation with Fully Nonlinear Boussinesq Equations
Résumé
Numerical simulation of tsunami propagation in large basin across the ocean demands significantly high computational capability in terms of CPU time and memory allocation. Due to this limitation, the use of sequential codes in a single scientific workstation is possible only for small-scale tsunami problem. To overcome this difficulty, a parallel Boussinesq wave model is developed based on the original FUNWAVE sequential model for efficient simulation of long wave propagation, coastal inundation and runup. The numerical resolution is decomposed into small sub-domains using domain decomposition technique for each processor to perform the calculations. The wave information is exchanged between processors via message passing interface (MPI). We show the effectiveness of this parallel code on distributed- and shared-memory computer clusters in simulating two tsunami events: the 2004 Indian Ocean and the 1999 Vanuatu tsunamis. Communication in the overlapping domains and load balancing in the partitioned domains are considered to ensure the efficiency of this method. It is found that the performance of the parallel model for both large- and small-scale tsunami problems is very satisfactory. Finally, the parallel model is applied to a spatial hierarchical grids methodology for a location-specific numerical simulation. Grid sensitivity and improved simulation results for runups along Phang Nga coastline from Takua Thung to Khao Lak are presented.