Fast Numerical Model Based On Time-space Decoupled Algorithm Of Wave Equation For Tsunami Propagation

With the increasing population in the nearshore regions, more and morebuilding and infrastructure make our life more closer to the ocean. In recent years,however, the ocuurancy of tsunami made a huge destruction to infrastructure in thenearshore regions. In the process of tsunami, buildings and briges would sufferevident destruction, and the process of destruction is very complicate. The degree ofdestruction is depend on the wave amplitude of tsunami. Therefore, it is necessary tostudy the fast simulation of three processes which are generation, propagation andinundation in tsunami. With this fast tsunami simulation, human lives and propertyin the nearshore regions are become more and more safty.This paper introduced a new time-space decoupled numerical algorithm tohandle tsunami propagation process. Based on COMCOT, the new model with thetime-space decoupled numerical algorithm are adopted to simuale311Tohokutsunami, and the main content and conclusions are as follows:1. Introduce the numerical model COMCOT, including the generation model,governing equations, governing coordinate, the moving boundary and nesting gridsystem.2. Based on the research results and papers, a new time-space decouplednumerical algorithm is intoduced to handle tsunami propagation. The modifiedleap-frog finite difference method in COMCOT is replaced by the new algorithm tosolve linear shallow water equation in tsunami propagation. In order to consider thedispersion effect in tsunami propagation, the numerical dispersion in the newalgorithm is adopted to mimic dispersion effect in tsunami propagation.3. A new nesting grid system based on the new algoritm is introduced to satisythe order accuracy and dispersion effect in different regions.4. The311Tohoku tsunami is simulated by the new model, the simulationresults are compared with the results by COMCOT and DART measured data. Goodagreement between the new model and COMCOT demonstrate that the newalgorithm have the same accury to COMCOT, howerve, the new algorithm can savemuch more computation time. The discrepancy between simulated results andmeasured data may due to the complexity in311Japan Tohoku tsunami epicenter.