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为拓展主涡对并气动声场计算分析方法研究,针对亚声速平面混合层主涡对并流动,采用直接数值模拟(DNS)方法求解获取近场声源,利用二维Kirchhoff频域法和时域法外推声辐射远场,并应用Kirchhoff频域法对主涡二次对并声辐射特征进行分析。研究结果表明:Kirchhoff频域法和时域法具有一定差异性,但与主涡对并直接声计算结果对比,显示二者计算精度相当且均具有较高的精确性。通过Kirchhoff频域法应用分析,清晰揭示出主涡二次对并各声模态与主涡卷起、对并过程的对应相关性,利用频域法这种良好的计算分析性能,本文进一步研究了混合层入口扰动相位差对涡并声场的影响,展现出主导声波在声场中的重要作用。
In order to expand the main vortex pairs and study the calculation and analysis methods of the aerodynamic sound field, aiming at the main vortex pairs and the flow in the subsonic mixed layer, the direct numerical simulations (DNS) are used to obtain the near-field acoustic sources. By using the two-dimensional Kirchhoff frequency domain method and the time domain Extrapolation of the far-field of acoustic radiation, and Kirchhoff frequency domain method of the main vortex and the second analysis of the sound radiation characteristics. The results show that the Kirchhoff frequency domain method and the time domain method have some differences, but compared with the main vortex pairs and the direct acoustic calculation results, they show that both of the two methods have fairly high accuracy and high accuracy. Through the application of Kirchhoff frequency domain analysis, the corresponding correlations between the secondary modes of the main vortex and the modes of the primary vortex and the process of the primary vortex are clearly revealed. By using the good performance of frequency domain analysis and calculation, this paper further studies The influence of the phase difference of the mixed layer entrance on the vortex and the sound field is demonstrated, which shows the important role of the dominant sound in the sound field.