A nested grid based computational fluid dynamics model to predict bridge pier scour
A nested grid based computational fluid dynamics model to predict bridge pier scour
复制标题
基于嵌套网格的计算流体动力学模型来预测桥墩冲刷
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
T. Sturm
中科院分区：
文献类型：
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作者：
S. Baranya;N. Olsen;T. Stoesser;T. Sturm
本文应用一个计算水动力和地形动力的三维数值模型来计算圆柱周围的局部冲刷问题。一个嵌套网格的方法是实现在数值方案，以减少整体的计算需求，但在同一时间允许高的空间分辨率周围的圆柱体，以提高数值精度。计算网格由两个结构化块组成-一个粗略的块，离散化整个域和一个精细的块，只离散化圆柱周围的区域。一种新的插值技术实现了两个模块之间的通信。在形态动力学模型中的泥沙输移计算与推移质输移公式相结合的泥沙连续性方程再现不稳定冲刷坑的发展，而流场是重新计算在每个时间步。获得了室内动床渠道中单个和多个圆柱绕流及清水局部冲刷的试验数据，并与模型计算结果进行了比较。在所有情况下，都能很好地再现水流、最大冲刷坑深度和一般冲刷坑几何形状。冲刷的时间演变也被相当好地捕获。
A three-dimensional numerical model that computes hydrodynamics and morphodynamics is applied to the problem of calculating local scour around cylinders. A nested grid approach is implemented in the numerical scheme in order to decrease the overall computational demand but at the same time allow for high spatial resolution around the cylinder to increase numerical accuracy there. The computational grid consists of two structured blocks – a coarse block that discretises the entire domain and a fine block that only discretises the area around the cylinders. A novel interpolation technique accomplishes communication between the two blocks. Sediment transport in the morphodynamic model is calculated with a bed load transport formula combined with the sediment continuity equation to reproduce the unsteady scour hole development while the flow field is recalculated at each time step. Experimental data of flow and the local clear-water scour around single and multiple circular cylinders in a laboratory channel with a movable bed are obtained and compared with the results of the model. Flow, the maximum scour hole depth and the general scour hole geometry are reproduced well in all cases. The time evolution of the scouring is also captured reasonably well.