Numerical decoupling analysis of a resonator with absorbent material

Abstract

The purpose of this paper is to analyze the acoustic performance of resonators with porous material inside the expansion chamber. Sound wave propagation in the porous media is an extremely complicated phenomenon. In the present study the dynamic density and bulk modulus of air in the porous media are used to describe the viscous effects and the thermal effects in an air-saturated rigid frame porous material. With this assumption the absorbent material in the expansion chamber can be equivalent to a fluid with complex sound speed and wave number. Then the coupled equations for sound wave propagation in air (in straight tube) and the equivalent fluid (in expansion chamber) are solved by the numerical decoupling method. Finally, the effects of porous material on the performance of a resonator are discussed. ©