高雷诺数下双圆柱绕流诱发振动的数值模拟

基于表面涡方法研究了不同间隙比及归一化阻尼参数下,串列和并列双圆柱的流体诱导振动问题,并计算了圆柱的振动响应、流体力、振动频率等.结果表明:圆柱为刚性时的计算模拟结果与相关文献的实验结果吻合良好;在文中的研究条件下,串列双弹性圆柱具有屏蔽流的特征,涡脱落频率比刚性圆柱的大,其值主要取决于归一化阻尼而非间隙比;流体从并列双弹性圆柱分离的涡是对称的,与并列双刚性圆柱相比其平均力系数略小,但由于流体诱导振动造成的脉动力系数较大,故流体诱导振动对并列圆柱的动态响应有重要的影响.研究结果为亚临界雷诺数范围内热交换器管束的复杂流体诱导振动等问题提供了一种可能的计算方法.

Numerical Simulation for Flow Around Two Cylinders at High Reynolds Number by Surface Vorticity Method

The flow-induced vibration of two independently moving tandem cylinders and two independently moving side-by-side cylinders is simulated by surface vorticity method with different spacing and reduced damping parameters.The computational results of the cylinder response,the fluid force and the vibration frequency are presented.The simulation results of the flow around rigid cylinders well coincide with the experimental ones in the literatures.The tandem case shows that the two flexible cylinders exhibit the characteristics of a shielded flow and a higher shedding frequency than that of rigid cylinders,which primarily depends on the damping parameter rather than spacing ratio.The side-by-side results indicate that the vortices shed from the two flexible cylinders are symmetrical and the average forces of flexible cylinders are slightly smaller than that of rigid cylinders while the fluctuation forces caused by flow-induced vibration are larger,hence the flow-induced vibration exerts significant influence on the dynamic response of the cylinders.The proposed method enables to simulate complex flow induced vibration occuring in heat exchanger tube bundles at sub-critical Reynolds number.