NUMERICAL MODELING OF THE TURBULENT FLOW STRUCTURE THROUGH VERTICALLY DOUBLE LAYER VEGETATION

抄録

 In the present study, a turbulent flow structure through vertically double layer vegetation (DLV) as well as single layer vegetation (SLV) under steady subcritical flow condition of inland tsunami in an open channel was investigated computationally by incorporating a three-dimensional (3D) Reynolds stress turbulence model, using FLUENT. The numerical model showed the ability to capture inflection in velocity profiles close to the top of short vegetation height, and suggested the modeling of inflection over this mixing layer region of flow. The production of turbulent kinetic energy and dissipation of turbulent energy through the vegetation region was observed to be comparatively very high for DLV flow as compared to that of SLV flow, which suggested that incorporating short vegetation within tall vegetation significantly increases turbulence in the flow and dissipation of turbulent energy. The 3D simulation data of velocity and shear stress around the mixing layer was also used to derive important information that could be used in 2D modeling of flows through DLV.