基于雷诺平均法的四圆柱桩绕流数值模拟研究

为研究河海深水中水流对桥梁桩基础的动力学作用。文章基于 ANSYS/FLUENT 数值仿真软件,采用雷诺平均法研究四圆柱桩的绕流特征,分析 7 种不同迎流角及 3 种典型间距比下的四圆柱桩流场特征、各桩阻力系数及桩周床面所受切应力的分布。结果表明:迎流角与间距比均对四圆柱桩绕流特性有较强的影响;随迎流角从 $ 0^{\circ} $ 增大到 $ 45^{\circ} $,下游桩周床面切应力分布模式由屏蔽状态逐渐转变为分离流冲击状态;当间距比为 1.0 时,临界屏蔽角为 $ 5^{\circ} $;当间距比为 1.5 或 2.0 时,迎流角处在 $ 20^{\circ} \sim 30^{\circ} $ 之间,各桩阻力系数值均处于 $ 1.0 \pm 0.2 $ 范围,此时屏蔽效应最小。

In order to study the dynamic effects of water flow on bridge pile foundation in deep water, this paper analyzed the flow characteristics of four cylinder pile by using the Reynolds averaging method based on the ANSYS/FLUENT numerical simulation software, and studied the flow field characteristics of four cylinder pile under seven different angles of incoming flow and three typical spacing ratios, the drag coefficient of each pile and the distribution of shear stress on the bed surface around the pile. The results show that both the angle of incoming flow and the spacing ratio have a strong influence on the flow characteristics of the four cylinder pile. With the angle of incoming flow increasing from $ 0^{\circ} $ to $ 45^{\circ} $, the shear stress distribution mode of the downstream pile bed surface gradually changes from the shielded state to the separated flow impact state. When the spacing ratio is 1.0, the critical shielding angle is $ 5^{\circ} $. When the spacing ratio is 1.5 or 2.0, and the angle of incoming flow is between $ 20^{\circ} $ and $ 30^{\circ} $, the drag coefficient of each pile is in the range of $ 1.0 \pm 0.2 $, and the shielding effect is minimal.