低雷诺数变截面细长柔性结构流固耦合能量交换特征分析

Analysis of Fluid-Structure Coupling Energy Transfer Characteristics Slender Structure with Variable Cross-Section at Low Reynolds Number

波浪形变截面柱体结构具有良好的流动减阻特性,然而尚不清楚这种变截面柔性结构的流致振动特性.基于高精度谱单元法建立了细长柔性结构的流固耦合力学模型和高精度算法,对在低速均匀流作用和驻波初始动力激励下的流致振动机理进行了数值分析,阐明了波浪形细长柔性结构的尾流特性、结构动力响应特性、能量传递规律、涡脱频率的展向变化特征,也对减阻、减振机理进行了初步探讨.数值模拟结果表明,在合适截面扰动波高下波浪形变截面柔性结构能够大幅抑制涡激振动响应,并发现在波浪形细长结构两侧形成的特殊涡结构会稳定绕流剪切层,拉长涡旋形成区长度,从而降低尾流结构与结构的流固耦合效应,抑制涡激振动响应.

The wavy deformed cross-section cylindrical structure has excellent properties of drag reduction in fluid flow,but the flow-induced vibration characteristics of flexible structure with such variable cross-section are still unclear.In this paper,based on the high-performance spectral element method,a fluid-structure coupled mechanistic model and a numerical algorithm for slender structures are established.The wake characteristics,structural dynamic responses,energy transfers,and spanwise variations of vortex shedding frequencies are discussed.The numerical simulation results show that slender structure with the wavy-deformed cross-section can greatly suppress the vortex-induced vibration response at an appropriate cross-section disturbance wave height,and the special vortex structure formed on both sides of the wavy-shaped slender structure can stabilize the flow around the shear layer and elongate the vortex formation length,thereby reducing the fluid-structure coupling effect between the wake structure and the slender structure,and suppressing the vortex-induced vibration response.