不同间距比下串联圆柱涡激振动数值模拟研究

Numerical simulation research on vortex-induced vibration of series cylinders with different spacing ratios

针对不同间距比下小尺寸串联双圆柱在双自由度下的涡激振动位移响应,受力特性以及运动轨迹等进行仿真研究,应用Fluent中的SST k-ω湍流模型,采用Coupled算法实现速度与压力的耦合,基于Overset Mesh技术进行网格划分,运用动网格技术实现流固耦合。研究结果表明当S/D=3时,上游、下游两圆柱的“锁定”区间均为Vr=7-9,当S/D=4与S/D=5时,两串联圆柱的“锁定”区间范围增大。同时随着串联两圆柱间距比增大,上下游圆柱之间的影响逐渐减小,导致升力系数相应减小。随着约化速度增大,上下游圆柱的阻力系数均趋于稳定。当S/D=3时串联两圆柱运动的规律性较差,随着间距比增大上游圆柱“8”字形变得更加标准,下游圆柱轨迹则呈现多样化的特点。

The vortex-induced vibration displacement response,motion trajectory and vortex detachment mode of small-size series double cylinders with different spacing ratios under dual degrees of freedom are simulated and studied.Using the SST k-ω turbulence model in Fluent,the coupled algorithm is used to realize the coupling of velocity and pressure,the mesh is based on the Overset Mesh technology,the viscous N-S equation is solved by the Reynolds average method,and the fluid-structure coupling is realized by the dynamic mesh method.The research results show that the lock in interval of the upstream and downstream cylinders are both Vr=7-9 under the condition of S/D=3.The range of lock in interval of the two cylinders increases under the condition of S/D=4 and S/D=5.As the spacing ratio increases,the influence of the downstream cylinder on the upstream cylinder continues to decrease,and at the same time the lift coefficient decreases accordingly.As the reduction speed increases,the drag coefficients of the upstream and downstream cylinders tend to stabilize.When S/D=3,the regularity of the movement of the two cylinders in series is poor.As the spacing ratio increases,the 8 shape of the upstream cylinder becomes more standard,and the downstream cylinder trajectory shows diversified characteristics.