分形及规则布置方柱绕流场及气动噪声特性数值研究OA北大核心CSTPCD

In this study,large eddy simulations with the usage of the K-FWH equation are performed to numerically simulate turbulent flows behind two different kind of cylinder arrays(regular and multiscale)with the same blocking ratio.The large eddy simulation methods used in this paper are verified by the previous single-cylinder flow experiments and numerical results.The results show that the numerical method used in this paper can better predict the turbulent characteristics of the flow around the cylinder.Numerical results show that at the Reynolds number of 104,the mean drag coefficient of square cylinders with regular arrangement is approximately equal to that of the square cylinders with multiscale arrangement.Vortex shedding behavior in the case of regular arrangement present an obvious phenomenon of"phase locking",while the vortex shedding in the case of multiscale arrangement is rather chaotic.The far-field distributions of the sound pressure level of the two flow fields are approximately the same.The induced noises in case with the regular array also exhibit similar"phase locking"behavior.In contrast,multiscale arrangement can modify the distribution the noise spectrum and transfer the power from the low-frequency region to the high-frequency region.