Numerical Modeling and Experiments on Sound Propagation Through the Sonic Crystal and Design of Radial Sonic Crystal

Abstract

Sonic crystals are man-made structures consisting of sound hard scatterers placed in a periodic arrangement. Such structures have a unique property of selective sound attenuation in a specific range of frequencies which is determined by the geometry of the structure. In this work, different numerical models to model sound propagation through the sonic crystal are presented. Initially, a 1-D model based on the Webster horn equation is developed, which is later improved by the quasi 2-D model. Sound attenuation through the numerical models are compared with the experiments and finite element simulations, and it shows good agreement. Based on the 1-D model, a parametric study is performed to obtain some design guidelines for high sound attenuation.

The numerical model developed for the rectangular sonic crystal is extended to the polar coordinates to design a novel structure called as the radial sonic crystal. Instead of scatterers being placed in rectangular periodic arrangement, scatterers are placed in the polar coordinates around a point source. The design of radial sonic crystal is validated experimentally and using the finite element simulation. The result shows a high sound attenuation in the desired range of frequencies, which is due to the periodic design of the radial sonic crystal.