床面上直立圆柱的三维湍流数值模拟

THREE-DIMENSIONAL NUMERICAL MODEL FOR TURBULENT FLOW AROUND A BOTTOM-MOUNTED PILE

从数值预报桥墩等结构物床面局部冲刷的角度发展绕直立圆柱的三维湍流的数值模拟技术.基于Wilcox的κ-ω两方程湍流模式,采用基于有限体积法的压力修正SIMPLE算法,计算了绕床面直立圆柱的三维湍流流场,分析了光滑和粗糙床面两种情况下的流动情况.通过系列的验证计算,表明该计算模型能够比较准确地反映不同外来流条件下绕直立圆柱的流场.计算结果揭示了床面粗糙度对绕圆柱的湍流流动的影响.

When a bottom-mounted pile is placed in a steady current, the presence of the pile will change the flow pattern in its neighborhood, resulting in the following phenomena: the contraction of the flow, the formation of a horseshoe vortex in front of the pile and lee-wake vortices behind it. These changes usually cause an increase in the local sediment transport capacity, and thus lead to local scour. The three-dimensional flow around a vertical bottom-mounted circular pile is studied numerically by means of SIMPLE method based on the Finite Volume Method. The κ-ω turbulence model is used for closure. The mathematical model is validated against experimental data and numerical results available. Computational results show that the effects of roughness of bottom on the turbulent flow around a vertical bottom-mounted circular pile.