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本文对一亚音速圆口喷管内壁面施加盲孔,使其壁面多孔化,采用大涡模拟结合FW-H方法研究了马赫数M=0.6时喷管外的非稳态流场与远场噪声。研究结果显示,这种内壁小孔结构对喷管外流场的湍流脉动有一定的削弱作用。时空相关系数的对比表明,内壁小孔结构同时减弱了脉动量各自在时间和空间上的相关性,削弱了大尺度的涡结构。通过对涡强、膨胀率和Q涡识别准则的可视化分析,研究了剪切层中涡结构在喷流轴向的产生、发展与演化过程,结果表明内壁小孔结构抑制了涡配对现象,加强了流动掺混,从而加速了剪切层的发展。
In this paper, a blind hole was made in the inner wall of a subsonic circular nozzle, which made the wall porous. The large eddy simulation combined with FW-H method was used to study the unsteady flow field and far-field noise . The results show that this kind of inner wall pore structure has a certain weakening effect on the turbulent pulsation of the nozzle outer flow field. The comparison of spatio-temporal correlation coefficients shows that the pore structure of the inner wall weakens the correlation of the pulse amplitudes in time and space at the same time, and weakened the large-scale vortex structure. Through the visual analysis of the eddy-vortex strength, expansion rate and Q-vortex identification criterion, the generation, development and evolution of vortex structures in the shear layer in the jet stream are studied. The results show that the inner pore structure suppresses the vortex pairs and enhances Flow mixed, thus accelerating the development of shear layer.