基于剪切层扇形分层模型的射流声传播分析

Acoustic Propagation Analysis of Jet Flow Based on Stratified FanShaped Shear Layer Model

摘要:

通过计算流体力学建立一种扇形分层剪切层速度模型，并以此为基础用几何声学方法推导整个射流结构的声传播模型.以实际开口式风洞为研究对象，用数值仿真给出射流结构速度分布.建立速度随角度均匀变化的扇形分层剪切层速度模型.用声折射理论推导不同速度层之间的声传播.以声漂移量为指标对射流声传播模型进行声学风洞试验验证，证明本模型对声漂移量的预测精度更高，在高风速、剪切层较厚的情况下，优势尤为明显.

关键词:声传播; 射流; 剪切层; 几何声学

Abstract:

An acoustic propagation model of jetflow was deduced by geometrical acoustics based on the fanshaped stratified velocity model of shear layer built by CFD. Taken an actual openjet wind tunnel as research objects, the velocity characteristics of jetflow were given by numericalsimulation. A fanshaped stratified velocity model of shear layer whose speed changed uniformly with the angle, was built. The acoustic propagation between different velocity layers was deduced by using the sound refraction theory. The acoustic propagation model of jetflow was verified by aeroacoustic wind tunnel experiment which took sound source drift as the index. The results show that this acoustic propagation model is more accurate to predict sound drift. In conditions that jet flow velocity is high and shear layer thickness is large, the improvment is particularly evident.

Key words:acoustic propagation; jet flow; shear layer; geometrical acoustics