摘要
通过求解二维非定常雷诺平均Navier-Stokes方程,对亚音速情况下长宽比为L/D=2的空腔流动进行了计算气动声学数值模拟研究．湍流模型选取标准κ-ε模型,空间离散采用频散相关保持格式,时间积分采用低耗散低频散龙格库塔法,进出口远场边界采用以摄动解为基础的无反射边界条件．计算结果首先与Krishnamurty实验观测的密度场纹影图进行了对比,不论是在腔内流场分布还是腔外辐射指向性上,都与实验结果符合较好；然后与Rossiter公式进行了频率对比,其结果不但较为准确地捕捉到了振荡低阶模态的频率,而且也捕捉到了振荡高阶模态的频率特性．在此基础上研究了边界层厚度对振荡性质的影响,研究表明边界层厚度对振荡幅值影响较大,而且使振荡频率发生小幅偏移．最后探讨了振荡的发声机理,分析了振荡发声及声反馈的过程,发现了空腔前缘的二次发声现象．
By solving the two-dimensional unsteady Reynolds averaged Navier-Stokes（URANS） equations, the flow-induced oscillation and sound generation are investigated with a computational aeroacoustics approach. The dispersion-relation-preserving scheme is applied for spatial discretization and the low-dissipation and lowdispersion Runge-Kutta scheme is adopted for time integration. The standard κ-ε turbulence model is employed in the stmulation. Appropriate non-reflecting boundary conditions are adopted at the inflow and outflow boundaries. The simulated density field agrees well with Krishnamurty＇s experimental schlieren photograph. And the first three oscillation modes have been caught and are found to agree very well with the predicted frequencies by Rossiter＇s empirical formula. Furthermore, it is shown that the thickness of the boundary layer has an important influence on the self-sustained oscillation. Finally, the sound generation mechanism of the oscillation is analyzed and the second sound wave generation phenomenon is detected at the leading edge.
出处
《力学学报》
EI
CSCD
北大核心
2006年第5期599-604,共6页
Chinese Journal of Theoretical and Applied Mechanics
基金
国家自然科学基金(10472010)
高等学校博士学科点专项科研基金(200500602资助项目.~~
关键词
空腔流动
自持振荡
数值模拟
计算气动声学
cavity flow, self-sustained oscillation, numerical simulation, computational aeroacoustics
