NUMERICAL CALCULATION OF THREE-DIMENSIONAL FLOWS IN AN OPEN CHANNEL WITH A RUBBLE MOUND GROIN BY USING NON-DARCIAN RESISTANCE LAW

摘要

This study presents a combined numerical model of a porous flow model that adopts the non-Darcian resistance law and a 3-dimensional Large Eddy Simulation model in order to investigate three-dimensional and temporal structures of flows around a rubble mound groin. The model's accuracy is cross-checked by comparing the numerical results to the observed results of an existing experiment. The model's results show good agreement in terms of time-and depth-averaged sense. Calculation results also suggest that a permeable groin restricts growth of secondary flows in a constriction section. However, a combined model is not able to produce unsteady characteristics of flows that are caused by small scale and structured turbulences in a down-stream region of a groin.