SIMULATION OF THE EFFECT OF FAR FIELD TSUNAMI THROUGH AN OPEN BOUNDARY CONDITION IN A BOUNDARY-FITTED CURVILINEAR GRID SYSTEM

A new approach is developed to simulate the effect of far field tsunami in a limited area model domain where the coastal and Island boundaries are curvilinear in nature and the bending is high. The model is designed in a boundary fitted curvilinear grid system. To simulate the effect of far field tsunami, it is considered that the tsunami source is located far away from the model domain. The coastal and island boundaries and the other open boundaries of the model domain are represented by some functions so as to generate the boundary fitted grids. To use the regular finite difference scheme a transformation is used so that the physical domain is transformed into a rectangular one. The transformed shallow water equations are then solved in the transformed domain. The response of the tsunami source due to 26 December 2004 Indonesian tsunami is computed along the western open boundary of the model domain. Based on the response of the tsunami source, an appropriate boundary condition is formulated to simulate the effect of far field tsunami along the coastal belt. All simulations show excellent agreement with the observed data.