Abstract
In this study, we have developed an unresolved coupling model based on a drag model for Computational Fluid Dynamics (CFD) and Finite Element Method (FEM) using beam element. The proposed method involves conducting structural analysis by considering the fluid forces obtained through the drag model as external forces. Simultaneously, fluid analysis is performed, taking into account apparent volume changes and alterations in the flow field around the beam element.As a result, even in cases where the spatial resolution of the fluid is coarse concerning the dimensions of the beam element, coupled calculations based on the drag model become feasible as long as the velocity field is appropriately obtained. Consequently, this approach proves to be suitable for large scale tsunami-structure interaction problem, including the process of houses in a coastal area being washed away by a tsunami.In the presentation, we elucidate the formulation and implementation of the proposed methodology, and present validation results regarding the fluid forces acting on beam elements subjected to unsteady free-surface flow. Furthermore, to demonstrate the utility of the proposed approach, simulation results are presented where a wooden house models is subjected to flows mimicking a tsunami, leading to their loss.