非均匀温度分布区中的声波传播有限元模型

A Finite Element Model of Sound Propagation in Regions with Non-Uniform Temperature

非均匀温度分布的空气介质将对声波的传播产生扰动.为了精确描述非均匀介质中的声传播特性,采用有限元法研究了声波的频率、入射角以及非均匀介质的温度分布特性对声传播的影响,着重分析计算了斜入射声波的传播问题,探讨了提高非均匀介质对声波反射系数的方法.仿真结果表明,声波在非均匀温度区中的传播特性主要由介质温度分布参数和声波入射角决定,其反射系数近似为声波穿越非均匀介质长度的周期函数.当入射声波参数和非均匀介质的温度分布特性之间满足一定条件时,声波将在介质界面上发生强烈反射,甚至全反射,这为声波传播路径的有效控制提供了灵活的技术手段.

Gases with non-uniform temperature distributions will disturb the propagation of sound. To study the sound propagation in non-uniform media, the effect of sound frequency, angle of incidence, and temperature distribution profiles on sound propagation was analyzed by using finite element method （FEM）. Special attention was given to the sound propagation at oblique incidence and the way to increase the sound reflection coefficients in media. The theoretical results show that the gas temperature distribution and incident angle are the primary cause for the sound reflection coefficient. The reflection coefficient is approximatively a periodic function of high temperature region width（ relative to the disturbance wavelength）. Owing to the strong reflection, even total reflection, in non-uniform media, a suitable technical approach can be developed for sound management.