二维时间发展混合层噪声的直接数值模拟

发布时间：2018-05-20 02:40

本文选题：直接数值模拟 + 时间发展混合层　；参考：《西安交通大学学报》2017年01期

【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。
[Abstract]:In order to investigate the effect of the initial disturbance of different wavelengths on the flow and noise in the two-dimensional time-developing mixed layer, the direct numerical simulation method is used to study the effects of the initial disturbance on the flow and noise of the mixed layer. The mass, momentum and energy conservation equations are recovered from the Boltzmann equation of the coupled double distribution function by using the multi-scale expansion technique, and the characteristic boundary conditions and Boltzmann equation are fused to satisfy the non-reflection characteristic of the boundary. The Boltzmann equation is solved by using the time-space discrete scheme with high accuracy and the mixed layer of time development under five different working conditions is directly simulated. The results show that the high frequency disturbance mainly controls the alignment and winding of the vortex in the mixing layer, the low frequency disturbance mainly controls the migration and rotation of the vortex, and the evolution process of the vortex pair is similar to that of a rotating quadrupole source model. The disturbance can radiate to the far field in the form of plane waves and propagate at the local sound speed. The results can be used as a reference for the study of turbulent mechanism in mixed layer.
【作者单位】：西安交通大学叶轮机械研究所;
【分类号】：O357.5

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