小直径附加圆柱对圆柱涡激振动抑制的参数优化

Parametric optimization for vortex-induced vibration suppression of a single cylinder with two small cylinders symmetrically arranged in rear

采用基于迭代嵌入式浸入边界法对后方对称布置两个小直径圆柱的单圆柱涡激振动进行了数值模拟研究,对涡激振动抑制进行了参数优化。雷诺数和圆柱直径比分别为Re=100和d/D=0.125,其中D和d分别为大、小圆柱直径。通过改变控制角度(θ)、主圆柱与小圆柱的间隙比(G/D)、小圆柱旋转角速度和旋转方向(α)和阻尼比(ζ)确定的最优控制参数组合为θ=25°、G/D=0.125、α=-2.2和ζ=1.02。小圆柱的旋转角速度和旋转方向对圆柱振幅有一定的影响,其中内向反转会进一步抑制圆柱的振动,外向反转则恰好相反。随着阻尼比的增加,圆柱振幅先增后减,但影响程度较小。

Numerical simulations were done for vortex-induced vibration of a single cylinder with two small cylinders arranged in rear using the immersion boundary method based on iterative embedded form to optimize parameters of vortex-induced vibration suppression.Reynolds number and the diameter ratio of small cylinder to main one were Re=100 and d/D=0.125.The simulation results showed that the optimal control parameters are determined as follows:θ=25°,G/D=0.125,α=-2.2 andζ=1.02 through changing control angle(θ),gap ratio between small cylinder and main one(G/D),small cylinder’s rotating speed and rotating direction(α)and damping ratio(ζ);small cylinder’s rotating speed and rotating direction have a certain effect on main cylinder’s vibration amplitude;the inward counter-rotating(IC)can further suppress main cylinder’s vibration,while the outward counter-rotating(OC)has the opposite effect;main cylinder’s vibration amplitude firstly increases then decreases with increase in damping ratio,but its influence level is smaller.