锯齿射流与圆射流流场和远场噪声特性的对比研究（英文）

发布时间：2019-01-06 07:36

【摘要】：采用大涡模拟研究了高亚音速、基于直径Reynolds(雷诺)数为Re=105的圆喷管构型射流和6齿喷管与4齿喷管构型的锯齿射流.将圆射流的计算结果与前人已有的实验和大涡模拟结果进行了对比,验证了当前计算结果的可靠性.对比研究了锯齿射流与圆射流特征,结果显示锯齿射流在近喷口附近具有更大的径向扩张率和更短的势核区长度;锯齿射流的总声压级在低辐射角度上相比于圆射流可低4 dB,而在侧边辐射方向噪声没有明显升高.分析了锯齿射流和圆射流远场压力脉动的前三阶周向Fourier(傅里叶)模态m=0,1,2,结果显示三组算例在同一周向模态上呈现出相似的声压级分布,然而4齿锯齿射流的第零阶和第一阶周向模态在高辐射角度上相较于圆射流具有更高的噪声水平.将POD分解技术用于提取特定周向模态上的最具能量的大尺度结构,在与大尺度结构相关的波包特征角度部分解释了锯齿射流和圆射流远场噪声特性的不同.
[Abstract]:The high subsonic circular nozzle jet with diameter Reynolds (Reynolds) number of Re=105 and the sawtooth jet with 6-tooth nozzle and 4-tooth nozzle configuration are studied by large eddy simulation. The calculated results of the circular jet are compared with the experimental results and the large eddy simulation results, and the reliability of the present results is verified. The characteristics of sawtooth jet and circular jet are compared. The results show that saw tooth jet has larger radial expansion rate and shorter nucleation region length near the nozzle. The total sound pressure level of the sawtooth jet is 4 dB, lower than that of the circular jet at low radiation angle, but the noise in the side radiation direction does not increase obviously. The first three order circumferential Fourier (Fourier transform) mode mP0 1 / 2 of the pressure pulsation in the far field of the jagged jet and the circular jet is analyzed. The results show that the three sets of examples show similar sound pressure level distribution in the same circumferential mode. However, the zero-order and first-order circumferential modes of the 4-toothed jagged jet have higher noise level than the circular jet at the high radiation angle. The POD decomposition technique is used to extract the most energetic large scale structures in specific circumferential modes. The difference between the far field noise characteristics of the sawtooth jet and the round jet is explained in the wave packet characteristic angle related to the large scale structure.
【作者单位】：中国科学技术大学近代力学系;
【基金】：Project supported by the National Natural Science Foundation of China(11232011;11402262;11621202;11572314)~~
【分类号】：O358

【相似文献】