轴向流中两平行弹性薄板大挠度流固耦合系统的数值模拟

研究了轴向流中两平行弹性薄板大挠度流固耦合系统的振动响应和流场特性.板的结构动力学方程采用基于位移的有限元法离散,流场采用完全的二维不可压缩粘性流体N-S方程,用有限体积法离散,结合动网格控制技术,建立了模拟轴向流中两平行悬臂弹性薄板双向流固耦合作用的二维数值模型,实现了弹性薄板—流体—弹性薄板之间的交互作用.利用该数值模型得到了单块板的流致振动特性;发现了随着两板间距大小的不同,两板表现出三种不同的的极限环振动:同相位、异相位以及不确定相位,并得到了同相位与异相位两种振动状态下的板边界层脱落及尾流变化规律;另外,分析还发现在同相位和异相位过渡阶段,两板均表现出拍现象.

Fluid-Structure Interaction Simulation of Two Parallel Elastic Plates withLarge Deformation Subjected to Axial Flow

The dynamic behavior and flow field characteristics of two parallel elastic plates with large deformation subjected to axial flow are studied numerically.The structural dynamics equation is discretized by isoparametric displacement-based finite elements,and the motion of a continuous fluid domain is governed by two-dimensional incompressible viscous Navier-Stokes equations,which is discretized by finite volume method.The two-dimensional numerical model of two-way fluid-structure coupling is established combined with moving mesh technology,realizing the interaction of elastic plates and axial fluid.The flow-induced vibration of a single plate is studied using the numerical model.Three different limit-cycle oscillations modes are found with the different distance between the two plates:in-phase oscillation,out-of-phase oscillation,and indefinite oscillation.The plate boundary layer shed from its free end and the wake are obtained under the in-phase and out-of-phase modes respectively.In addition,it is found that the two plates show beating effect in the transition from in-phase mode to out-of-phase mode.