Numerical Simulations of Tsunami Wave Properties on Coastal Slopes using One Piston-Wavemaker Method

Abstract

Most of the coastal area in the Ulee Lheue Bay of Aceh Besar was affected by a tsunami wave during the 2004 Indian Ocean Tsunami. Such area has an inclined bed floor which varies in slope. Variations of slope can affect tsunami wave properties such as tsunami arrival time, wave height and velocity. With those variations, the degree of the tsunami effects is highly unpredictable. Therefore, it is important to conduct a research to understand the effects of coastal slopes on tsunami waves propagations and wave deformation. Google SketchUp was used for designing the coastal slopes’ 3 Dimensional models. For the tsunami waves, solitary waves were generated by using smoothed particle hydrodynamics numerical models through the DualSPHysics software. The computation was based on the meshless method. From the simulations, the waves’ properties were obtained and were analyzed how coastal slopes affect the arrival time of tsunami waves, also for their height and velocity. Results show that the steepest coastal slope has the highest velocity, but shortest wave height and longest arrival time. Conversely, the flattest coastal slope has the lowest velocity, but highest wave height and shortest arrival time. Longer tsunami arrival times will benefit people in the evacuation process during the hazard.