亚声速热射流声源模型的应用（英文）  

Application of Sound Source Models to the Heated Subsonic Jet

作　　者：张星辰[1] 杨海华[1] 万振华[1] 孙德军[1] 

机构地区：[1]中国科学技术大学近代力学系,合肥230027

出　　处：《应用数学和力学》2016年第12期1308-1323,共16页Applied Mathematics and Mechanics

基　　金：Project supported by the National Natural Science Foundation of China(11232011;11402262;11621202)~~

摘　　要：对亚声速转捩热射流中失稳波相关的噪声产生机制进行了研究,并与冷射流中的结果进行了对比.基于时均大涡模拟(LES)流场,通过求解线性抛物化稳定性方程(LPSE)得到了失稳波的空间演化特性,然后基于LPSE的解与声比拟方法构建了射流的线性及非线性声源模型.LPSE结果表明,加热可以提高失稳波的空间增长率,使其更早达到饱和.由线性模型分析可知,加热会提高高频模态的声压级(SPL).与冷射流相比,热射流中线性模型预测的声压级与大涡模拟结果间的差距更小,表明线性机制在热射流中作用更大.在亚声速冷射流中,非线性模型在之前的研究中已经被证明可以提高声辐射效率.在当前热射流中,发现非线性模型与大涡模拟间的声压级差距被进一步的缩小,且温度相关的声源项在声辐射中发挥更重要的作用.The noise generation mechanisms associated with instability waves in the heated subsonic transitional jet are studied, which are compared with its cold counterpart. The spatial evolution of instability waves is obtained by solving linear parabolized stability equations （LPSE） based on the time-averaged flow field of the large eddy simulation （LES）. Then, the linear and nonlinear models for jet noise are built based on the LPSE solutions, coupled with the acoustic analogy. The LPSE results show that heating increases the spatial growth rate and leads to earlier saturation. For high-frequency components, the sound pressure levels （SPL） are raised by heating as shown in the linear model. In general, compared with that for the cold jet, the gap of SPL between the linear model and the LES is reduced for the heated jet, which indicates that the linear mechanism plays a more important role in the hot jet. For a cold sub- sonic jet, previous studies have shown that the nonlinear model is able to raise acoustic effi- ciency. Here, it is found that the gap of SPL between the nonlinear model and the LES could be further decreased in the hot jet, and the thermodynmnic sound source terms play a bigger role.

关 键 词：线性抛物化稳定性方程 失稳波 线性机制 非线性机制 

分 类 号：O35[理学—流体力学]