• 作者： CHIN-LIEN YEN, JIHN-SUNG LAI, AND WEN-YI CHANG
• 中文摘要： By combining a three-dimensional (3D) flow model with a scour model, a morphological model has been constructed to simulate the flow field and bed evolution around bridge piers. The large eddy simulation (LES) approach with Smagorinsky's subgrid-scale (SGS) turbulent model is employed to compute 3D flow velocity and bed shear fields. For relatively coarse bed materials, the scour model solves the sediment continuity equation in conjunction with van Rijn's bed-load sediment transport formula to simulate the bed evolution. Without recomputing the 3D flow field as the bed deforms, the shear field obtained from the 3D flow model under flatbed conditions is modified according to the bed deformation. The 3D flow model is verified with experimental data obtained under flatbed conditions. The gravitational effect of the sloping bed of the scour hole on sediment particle movement is incorporated as part of the effective bed shear stress in the scour model. The scouring effect resulting from downflow in the region in front of the pier is included in the model by referring to the vertical jet flow scour relation. The measured data of scour evolution at the pier nose obtained by R. Ettema and bed elevation contours around a pier obtained by G. H. Lin are used for calibration and verification of the model. The results show good agreement between simulation and experimental nesults.
• 英文摘要： --
• 中文關鍵字： pier, scour, 3D flow, downflow, bed shear stress
• 英文關鍵字： --