Acoustic Wave Propagation In Non-Uniform Medium

Acoustic wave propagation through non-uniform medium has a very wide application. Using principle of acoustic propagation in an inhomogeneous medium, The acoustic thermometer, acoustic leak detectors and acoustic cleaning device has been widely used in the real world.In order to study the sound propagation in non-uniform media accurately, this paper builds the model of the finite element method (FEM) and studies acoustic wave propagation in one-dimension non-uniform media, study the effect of the frequency of sound, the incident angle, temperature distribution profile in the medium on reflection coefficient mostly, at the same time they are optimized for a certain goal.The propagation of planar sound waves through non-uniform medium regions may undergo substantial modification. Gas temperature gradients in the non-uniform gas region were believed to be the primary cause for wave modification. Analytical solutions of Helmholtz equation for plane sound transmission were obtained in gas waveguide with non-uniform media density along the sound propagation direction. We study sound wave propagation in two-dimension non-uniform media on base of one-dimension model, one hand, according to the Helmholtz equation in the idea conditions, we use variational methods to get the FEM equation, then solve the equation through making programming, the other hand, we used software to simulate sound propagation in the non-uniform medium waveguide and compared the results with that obtained by programming, found that these results were comparable.Finally, on the basic of the result that acoustic frequency, non-uniform dielectric thickness and the temperature gradient have an effect on the coefficient of sound wave propagation, the channel structure adapting for propagation of sound wave was optimized.