Numerical Experiments on Tsunami Wave Forces on Open Structures Using Dam-Break Method

Abstract

Open wall structures, such as those found in mosques, sustained large forces generated by a tsunami as in the case of the 2004 Indian Ocean tsunami. Although the surrounding buildings were flattened, there were a number of mosques in the tsunami affected area could still stand in the middle of the area. These motivated this study to look into more details the hydrodynamic forces generated around the open structures. This research was aimed at investigating the tsunami wave forces on open structures and at knowing relation between the tsunami waves velocity and the pressures on the pillars of the open structures. DualSPHysic was used to simulate the tsunami wave forces on the structures. The DualSPHysic is a smoothed particle hydrodynamic model with mesh-less method. We simulated 12 numerical simulations by constructing a-130 m wave flume equipped with dam-break at one end to generate the tsunami-like flows. A sloping bed was placed in front of an open wall structure. Four pillars were set to imitate a simplified model of open wall structure. Numerical observation points were placed at offshore part of the model, in front of the pillars (lee-side) and at the back of the pillars (wake-side). Simulations were performed for about 6 seconds started from releasing the dam gate and before the flow being reflected by the other end of the flume. This study proved that the impacts of the tsunami-like forces are more significant of the front row of the pillars. Meanwhile, tsunami wave forces at the back row of the pillars group are inconclusive to the wave velocity and wave heights.