非对称粗糙带对单圆柱流致振动特性影响研究

Research on fluid-induced vibration of single circular cylinder with asymmetrical roughness strip

本文采用非定常RANS方法和Spalart-Allmaras湍流模型,结合FLUENT软件动网格技术和用户自定义函数功能编写程序,对大范围雷诺数下非对称粗糙带单圆柱流致振动进行数值模拟,并与实验数据对比,讨论了非对称粗糙带单圆柱流致振动的振幅、频率、尾涡模式和功率等。其主要结论有:非对称粗糙带单圆柱流致振动捕捉到了正负向不同的振幅值,粗糙带侧振幅值小;非对称粗糙带单圆柱振幅比曲线捕捉到了初始分支、上分支、上分支-驰振过渡分支和驰振分支;相对于光滑圆柱,非对称粗糙带对上分支有明显的拓宽作用;随雷诺数增大,尾涡模式由2S过渡为非对称的2P且尾涡被逐渐拉长;同对称粗糙带圆柱相比,非对称粗糙带圆柱流致振动在上分支有更大的输出功率;数值模拟得到的非对称粗糙带单圆柱流致振动最大输出功率为6.62 W,实验所得最大输出功率为7.29 W。

Single circular cylinder with passive turbulence control is studied using unsteady Reynold-Averaged Navier-Stokes with Spalart-Allmaras turbulence model in a wide range of Reynolds numbers,and combining dynamic mesh with user defined function in FLUENT.Numerical simulation results are compared with experimental results for detailed analyses about amplitude,frequency,wake vortex mode and power etc.The main conclusions are:the amplitude of a cylinder with asymmetrical roughness strip is different in positive and negative,which is smaller in the side of roughness strip;Initial branch,upper branch,upper-galloping transition branch and galloping branch are observed in amplitude ratio curve;Compared with the smooth cylinder,the asymmetric rough strip has obvious broadening effect on the upper branch;Vortex mode changes from 2S to 2P with the increase of Re,where the 2P is asymmetric;Compared with the symmetric rough strip cylinder,flow induced vibration of the asymmetric rough strip cylinder has greater output power at the upper branch;The maximum output power is 6.62 W by numerical simulation in this paper and experimental data is 7.29 W.