하천합류부의 흐름모의를 위한 EFDC의 민감도 분석

Flow structure of river confluent shows complex hydraulic properties, which show separation zone, shear plane, and erosion. In this study, the hydrodynamic module of EFDC (Environmental Fluid Dynamics Code) was used to simulate flow in the confluent channel, and the sensitivity analysis of parameters, which were grid resolution, horizontal eddy viscosity, and the number of vertical layer, were conducted. The sensitivity analysis results show that the results in coarse grid provided underestimated velocity and overestimated water depth even though the CFL condition was satisfied. The lateral variations of velocity was decreased by increasing of the horizontal eddy viscosity, and the error was increased when the diffusion by eddy viscosity was larger than the advection by flow. The magnitude of vertical velocity at the bottom layer can be overestimated the erosion at the confluent if the number of vertical layer is less than 10.