Propagation Of Sound Waves Through Regions With Non-uniform Temperature

Acoustic wave propagation technology has a very wide application. The technology of temperature gradient acoustic wave controlling is used to achieve more and more cause for concern.In order to study the sound propagation in non-uniform media, this paper builds the model of ray method and the finite element method (FEM) and studies on the acoustic wave propagation, the effect of sound frequency, angle of incidence, and temperature distribution profiles on sound propagation was analyzed. Special attention was given to the sound propagation at oblique incidence and the way to increase the sound reflection coefficients in media.Ray method is based on similar multiple layers of non-uniform temperature, each interval meet three basic laws , iterating to calculate layer by layer, so the analytic solution of acoustic wave propagation can be obtained.The theoretical results show that Ray method can largely reflect the general trend of acoustic wave propagation, but there are some limitations, in particular, can not be in the higher frequency sound waves to meet the requirement of the convergence of computing.FEM divided the non-uniform area into discrete units, then merged the total stiffiiess matrix and used conjugate gradient method calculate for the synthesis of large-scale matrix, so the numerical solution of acoustic wave propagation can be obtained . FEM mehthod shows that it is an effective solution to the problem of sound wave propagation, can be a good ananysis of acoustic wave propagation characteristics,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.