完全湍流剪切层对圆柱涡激振动特性的影响

摘要

To study the dynamic response of vortex-induced vibration under different oα in TrSL3 (Transition of shear layer,2× 104-4× 104＜ Re ＜ 1 × 105-2× 105),the finite-volume method is used to resolve the turbulence model of the Reynolds-averaged Navier-Stokes equation and the Spalart-Allmaras equation on the basis of OpenFOAM together with the Van Der Pol second-order equation describing the two-dimensional vortex-induced vibration of cylinder.The oscillating amplitude,frequencies and the vortex shedding structures are analyzed in detail.The initial,upper and lower branches of the synchronization phenomenon in vortex-induced vibration are captured.The results show that,the amplitude in present work is higher than that in TrSL2 and modified Griffin plot when evaluate Reynolds number under the same reduced velocity.Reynolds number plays a key role in elevating the oscillating amplitude and the synchronization range under TrSL3.The vortex-induced vibration misses upper branch and enter into the lower branch directly from initial branch in the case of high mass-damping ratio (α ≥ 0.38),phase step occurs in oscillating frequency.%为研究完全湍流剪切层(2×104～4×104＜ Re＜1x105～2x105)下雷诺数对涡激振动动态响应的影响,在OpenFOAM平台下采用有限体积法求解雷诺平均Navier-Stokes方程和Spalart-Allmaras一方程湍流模型,采用二阶范德波尔方程描述二维圆柱体涡激振动,对完全湍流剪切层下的圆柱绕流涡激振动进行数值计算,分析涡激振动的振幅、频率特性,并在Williamson-Roshko(W-R)图谱中分析旋涡尾迹脱落模式.结果表明:在相同折减速度下提升雷诺数时,圆柱振幅会显著增大,最大振动振幅值高于自由剪切层过渡旋涡区结果及修正Griffin图谱结果.雷诺数对提高圆柱的涡激振动振幅和同步区的范围具有决定性作用,在完全湍流剪切层中,当提升阻尼参数(α≥0.38)时,涡激振动的上部分支消失,振动频率出现“阶跃”.