圆柱-尾流隔板系统流致旋转振动的低维模型研究

Reduced-order Model for Flow-induced Vibration of Rotatable Circular Cylinder with Rigid Splitter Plate

在圆柱尾流区内增设可旋转的隔板是一种潜在的涡激振动控制方法,其优点是不仅可减小结构系统的流动阻力,而且具有对流向全角度适应性。论文采用高阶T-G迎风有限元方法求解ALE观点下的N-S方程,对均匀来流下圆柱-尾板系统的静力弯矩以及水动力系数项进行了计算。在此基础上建立了低维流固耦合降阶模型,全面考虑结构转动惯量、回转刚度、结构阻尼,以及流动附加转动惯量、流动附加阻尼、流体静力刚度和涡致激振力对振动的影响。与全耦合CFD数值计算结果的对比表明,建立的低维流固耦合动力模型能比较准确地预测结构的动力响应特性,特别是能对动力分叉的发生条件,以及分叉后的静平衡偏转位移作出较好预测,这是以往类似研究工作所未能解决的难题。这项研究建立的低维流固耦合动力分析模型对工程设计阶段的快速分析具有实用价值。

A circular cylinder attached to a rotatable splitter plate placed in the wake is often used to weaken the vortex-induced vibration with advantages of reducing drag force and good adaptability to the flow direction. In this work, a high-order T-G upwind finite element method is used to solve the Navier-Stokes equation within the ALE reference frame. The torque on the structure subjected to the steady flow and hydrodynamic coefficients of forced rotationally oscillating assembly in still water are calculated to establish a reduced-order model for predicting fluid-structure interaction. This model fully considers the structural moment of inertia, rotational stiffness, structural damping, the hydrostatic stiffness, the fluid moments of inertia and fluid damping due to the rotary oscillation with vortex excitations. Prediction of present reduced-order model and agrees well to that of the fully coupled CFD model, including the occurrence of bifurcated solution, equilibrium defection and rotary amplitude.