基于不同亚格子模型的冲击射流噪声特性研究

Numerical Study of Noise Characteristics of an Impinging Jet Based on Different Subgrid-scale Models

基于大涡模拟方法,采用三种亚格子模型对冲击射流的噪声特性进行了数值模拟,将模拟结果与实验数据对比分析,结果表明:Smagorinsky-Lilly(SL)模型数值耗散较大,模拟准确性较差;Wall-Adapting Local Eddy-Viscosity(WALE)模型和Kinetic-Energy Transport(KET)模型对总声压级的模拟结果比较准确;KET模型能够更加准确地模拟噪声频谱,而WALE模型对高频段噪声频谱的模拟误差偏大。最后,使用KET模型计算了噪声监测点在不同位置时冲击射流的总声压级,得到了不同冲击距离下的噪声指向分布情况。

Noise characteristics of an impinging jet are simulated using three different subgrid-scale models of large eddy simulation(LES). The simulation results are compared to experimental data.The results show that the Smagorinsky-Lilly(SL)model has more numerical dissipations and lower simulation accuracy. The Wall-Adapting Local Eddy-Viscosity(WALE)model and the Kinetic-Energy Transport(KET)model demonstrate good agreement with experimental data in the simulation of overall sound pressure level. The KET model can accurately capture the noise spectrum, whereas the WALE model displays some shortage in the simulation of high-frequency noise spectrum. Finally, the overall sound pressure level of noise monitoring points in different positions is calculated using the KET model. Noise directivity of the impinging jet is obtained under different impinging distances.