EFFECT OF MESH RESOLUTION ON NUMERICAL SIMULATION OF SEDIMENT TRANSPORT AROUND A CYLINDRICAL BRIDGE PIER USING REEF3D

Abstract

Scouring around bridge foundations installed within riverbeds can significantly affect structural safety, potentially causing pier overturning, settlement, or tilting owing to river-flow-induced scour and erosion. Such structural failures can disrupt transportation networks and significantly impact people's daily lives. Understanding and accurately predicting the scouring behavior around a structure is essential for ensuring the stability of bridge foundations and preventing structural failures. In this study, the applicability of scouring assessment methods was evaluated by a reproduction analysis conducted using REEF3D, an open-source computational fluid dynamics and wave modeling framework. REEF3D facilitates high-resolution simulations of sediment transport and scour processes via optimized hydrodynamic modules depending on the flow conditions. In this study, simulations were performed using three different mesh sizes to evaluate the validity of the numerical results through comparison with model test data.  The numerical simulation results successfully reproduced the general scouring tendencies around the pier, including the initiation of scour on the upstream side.  Furthermore, refining the mesh size improved the agreement with the experimental values in terms of the scour depth. However, the maximum scour depth was slightly underestimated compared with the experimental results.  These findings highlight the need for careful consideration of analytical conditions when numerically reproducing sediment transport phenomena observed in model tests.