二维时间发展混合层噪声的直接数值模拟  

Direct Numerical Simulation of Two-Dimensional Time-Developing Mixing Layer

作　　者：邵卫东[1] 李志刚[1] 李军[1] SHAO Weidong LI Zhigang LI Jun(Institute of Turbomachinery, Xi＇an Jiaotong University, Xi＇an 710049, China)

机构地区：[1]西安交通大学叶轮机械研究所,西安710049

出　　处：《西安交通大学学报》2017年第1期38-44,共7页Journal of Xi'an Jiaotong University

摘　　要：为了考查不同波长的初始扰动对二维时间发展混合层流动与噪声的影响,采用直接数值模拟的方法进行了研究。采用多尺度展开技术从耦合双分布函数玻尔兹曼方程中恢复出质量、动量和能量守恒方程;融合特征边界条件与玻尔兹曼方程来满足边界的无反射特征;运用高精度的时空离散格式求解玻尔兹曼方程并直接模拟了5种不同工况下的时间发展混合层。结果表明:高频扰动主要控制混合层中旋涡的对并和缠绕,低频扰动主要控制旋涡的迁移和旋转;涡对的演化过程类似于一个旋转的四极子源模型;扰动能以平面波的形式向远场辐射并且以当地声速传播。该结果可为混合层湍流机理研究提供参考。To investigate the influence of initial disturbance of different wavelengths on flow and noise of two-dimensional time-developing mixing layer,a direct numerical simulation method is suggested.By multiple-scale expansion technique,the conservative continuity,momentum and energy equations are accurately recovered from Boltzmann equation of coupled double distribution functions.The characteristic boundary condition is combined with Boltzmann equation to satisfy the non-reflecting condition. High-order temporal and spatial discretization approaches are employed to solve Boltzmann equation to analyze five different mixing layers.The results show that high frequency disturbances mainly control the pairing and winding of vortices,while low frequency disturbances mainly control the rotating and migration of vortices.The evolution of vortex pairing is similar to a rotating quadrupole source.The disturbance energy radiates as plane waves to the far field at sonic speed.

关 键 词：直接数值模拟 时间发展混合层 无反射边界条件 

分 类 号：O35[理学—流体力学]