不同截面形状柱体流激振动能量转换特性分析

Numerical analysis of energy harvesting from flow-induced vibration of cylinders with different cross sections

为了比较不同截面形状柱体的流激振动特性,探讨适用于流激振动能量转换的柱体截面形式,本文基于雷诺平均N-S方程,结合SST k-ω湍流模型和任意拉格朗日欧拉流固耦合动网格控制方法,对高雷诺数、高阻尼比条件下,圆柱、方柱、类梯形柱、梯形柱及T字形柱等5种不同截面形状的柱体流激振动进行数值模拟,模拟中保持各柱体的特征长度相同,质量比、阻尼比、同一流速下的雷诺数和约化速度等重要无量纲参数也均保持一致。计算结果表明:圆柱的振动表现为典型的涡激振动,其他4种柱体的振动均为驰振,在较低约化流速下T字形柱获得的功率均较其他柱体获得的为大。各柱体能量转换效率均随约化速度的增加先增大后减小,中间存在一个峰值,5种柱体中T字形柱的最大能量转换效率为最大,达到了42.5%,其次为圆柱,为27%。为了达到最大能量转换效率,圆柱和方柱所需要的流速最小,其次为T字形柱。从分析结果来看,T字形柱和圆柱对于低流速下的能量转换较为有利。

We compare the flow-induced vibration characteristics of cylinders with different cross-sectional shapes to identify the cross-sectional forms most suitable for flow-induced vibration based energy conversion.Based on the Reynolds-averaged Navier-Stokes equation combined with the SST k-ωturbulence model and the arbitrary Lagrange-Euler fluid-solid coupling dynamic-grid-control method,we numerically simulated the flow-induced vibration of cylinders with five cross-sectional shapes,i.e.,circular cylinder,square cylinder,trapezoid-like cylinder,trapezoidal cylinder,and T-shaped cylinder,under high Reynolds number and hight.In the simulation,we kept the characteristic length of each cylinder constant and the values of important dimensionless parameters the same,such as the mass ratio,damping ratio,and Reynolds number,at the same flow rates and reduced relocities.The results show that.The curves of energy conversion efficiency for all shapes show a peak.Of the five cylinder types,the maximum energy-conversion efficiency of the T-shaped cylinder is the greatest at 42.5%,followed by that of the circular cylinder at 27%.To achieve maximum energy-conversion efficiency,the flow velocities required by the cylinder and square cylinder are the smallest,followed by the T-shaped cylinder.Based on these analysis results,the cylinder and T-shaped cylinder are more favorable for energy conversion at low flow rates.