NUMERICAL INVESTIGATION OF FLOW AND TOPOGRAPHY CHANGE DUE TO TSUNAMI IN ABRUPT EXPANSION AREA USING A 3D RANS MODEL

Abstract

 In this study, numerical investigations using a 3D RANS model were conducted for flow and topography change induced by tsunami in an abrupt expansion area in order to reveal the applicability of the model for the phenomenon. The numerical results of flow simulations clarified that settings of side-wall boundary conditions have a huge effect on the reproducibility of a circulation flow in the abrupt expansion area, and the effect of the differences of turbulence models is small for the reproducibility. Moreover, from the numerical simulations of topography change, it was found that the effect of the non-equilibrium of bed-load transport is small under the targeted experimental conditions, and differences of calculation formulas of the suspended-load transport rate greatly affect the reproduction of the topography change.