圆柱非定常绕流及涡致振动的数值计算

Calculation of unsteady flow around circular cylinder and vortex-induced vibration

用基于一般曲线坐标系和交错网格的差分法求解原始变量二维不可压粘性流体的N- S方程 ,计算了雷诺数从 10 0到 1× 10 5范围内静止圆柱的非定常绕流和雷诺数从 5160到 630 0范围内的涡致振动。计算涡致振动时用动网格法分析圆柱和流体的耦合作用 ,N- S方程用二阶投影法和多重网格法求解 ,柱体的振动方程用 Newmark-β法求解。计算得到的静止圆柱涡脱频率和试验结果相当吻合 ,阻力系数令人满意 ,并成功地预测到了涡致振动的拍和锁定现象。

Numerical analysis of the unsteady flow around the stationary circular cylinder with Re (the Reynolds number) ranging from 100 to 10\+5 and its vortex-induced vibration with Re from 5160 to 6300 are conducted by solving the incompressible Navier-Stokes equations of initial variables in general curvilinear coordinates and staggered mesh. The vibration of the cylinder is studied by the moving-mesh method. A second-order projection method and the multigrid technique are used for solving the N-S equations. The response of cylinder is evaluated by the Newmark-β method. The vibration of the cylinder and the fluid flow are coupled by the boundary conditions on the surface of cylinder. The computed vortex shedding frequency agrees well with the experiment, and the obtained drag coefficient is satisfactory. The ‘beat’ and ‘lock-in’phenomena are successfully predicted. The computed amplitudes of vibration surprisingly agree well the experimental results.