Solving via Modular Methods
Solving via Modular Methods
复制标题
通过模块化方法求解
DOI：
10.1007/978-3-319-09186-0_1
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
S. Steidel
中科院分区：
文献类型：
--
作者：
Deeba Afzal;Faira Kanwal;G. Pfister;S. Steidel
近海结构的稳定性可能会受到局部冲刷的威胁，最终可能导致它们的失败。因此，对冲刷机理的了解和对冲刷特征几何形状的准确预测对于此类建筑物的设计是非常重要的。采用三维计算流体力学模型，计算了恒定流量和规则波两种不同边界条件下桥墩周围的冲刷和淤积形态。计算流体力学(CFD)模型求解所有三维的雷诺平均N-S方程(RANS)。自由面的位置用Level Set方法表示，该方法以非常逼真的方式计算自由面的复杂运动。对于波浪的实现，使用CFD程序作为数值波浪水池。对于动床的几何表示，采用了水平集方法。并将局部冲刷预报的数值结果与物理试验结果进行了比较。研究了湍流模型的性能、坡床的临界剪应力公式以及泥沙时间步长的变化对计算结果的影响。水动力时间步长和地形动力时间步长的解耦被检验并被发现是一个合理的假设。对于水流和波浪条件下的局部桥墩冲刷两种情况，数值模型准确地预测了冲刷坑的总体演变(几何形状、位置和最大冲刷深度)和时间发展。
Stability of offshore structures can be threatened by local scouring which could ultimately lead to their failure. As a consequence, knowledge of the scouring mechanism and the accurate prediction of the characteristic scour geometry is very important for the design of such structures. A three-dimensional computational fluid dynamics model is used to calculate the scour and the deposition pattern around a pier for two different boundary conditions: constant discharge and regular waves. The computational fluid dynamics (CFD) model solves Reynolds-Averaged Navier-Stokes (RANS) equations in all three dimensions. The location of the free surface is represented using the level set method, which calculates the complex motion of the free surface in a very realistic manner. For the implementation of waves, the CFD code is used as a numerical wave tank. For the geometric representation of the moveable sediment bed, the level set method is used. The numerical results for the local scour prediction are compared with physical experiments. The performance of the turbulence models, the formulations of the critical shear stress for the sloping bed and the effect of the variation of the sediment time stepping are investigated. The decoupling of the hydrodynamic and the morphodynamic time step is tested and found to be a reasonable assumption. For the two situations of local pier scour under current and wave conditions, the numerical model predicts the general evolution (geometry, location and maximum scour depth) and time development of the scour hole accurately.