淹没桥面板周围水流与局部冲刷的 CFD 数值模拟

摘要

本文采用基于水平集方法的多相水动力—泥沙动力数值模型 REEF3D，模拟淹没桥面板周围的水流条件与局部冲刷。水跃、桥面漫顶、承压射流及由此引起的冲刷，使所选算例从数值模拟角度极具挑战性。模型以试验资料加以验证，并考察了淹没比对水流与冲刷的影响。结果表明，水平集方法在处理复杂自由表面以及追踪可动床面方面均表现出良好的稳健性与精度；淹没比与冲淤型态之间未见明确的相关关系。由于数值模拟能够揭示其中的水动力过程，本文强调了数值模拟对此类复杂泥沙输移问题的重要意义。

Abstract

The level set method-based, multiphase hydro- and morphodynamic numerical model REEF3D is used for the simulation of the flow conditions and local scouring around submerged bridge decks. Presence of hydraulic jumps, bridge overtopping, pressurized jets and the resulting scouring make the selected test cases especially challenging from the numerical modelling point of view. The models are validated against experimental data. The influence of the submergence ratio on the prevailing flow and scouring is investigated. The level set method showed robustness and good accuracy for the treatment of the complex free surface as well as for the tracking of the mobile bed. The submergence ratio showed no clear correlation with the prevailing erosion/deposition patterns. As the simulations offered insights into the prevailing hydrodynamics, the relevance of numerical modelling was emphasized for such complex sediment transport problems.