INVESTIGATION OF TSUNAMI INDUCED LANDWARD SCOUR WITH XBEACH

Abstract

 XBeach is a numerical model for simulating coastal processes, including beach morphodynamics, dune evolution, and overwash processes. It is designed to simulate the response of the beach to various environmental factors, including waves. XBeach uses advanced numerical algorithms to solve the equations of motion and sediment transport and is capable of modeling the complex interactions between the ocean and the beach. Landward scour is the sediment’s hole behind the structure which is induced by overflowing flow during the extreme event, such as tsunamis and storms, which have high water depth and large velocity flow. This research is about modeling of landward scour phenomenon. The simulation results were compared against experimental results. This study shows that XBeach can model the morphodynamics shape of the scour hole. However, the scour depth as also suggested by other researchers for extreme overflowing setting is overestimated. Hydrodynamics parameters (water level) can be reproduced by the model with good agreement against the experiment although simulated flow velocity is slightly overestimated. It was also found that in a very short time scale phenomenon, as in the landward scour experiment, the model is sensitive to governing equation of sediment transport. An attempt to enhance the result by implementing artificial erosion limiter by using soil dilatancy improves the results, especially for erosion volume (V_err).