Noise calculation of noncompact bodies with impedance boundary in limited enclosed space

Abstract

The present paper mainly investigates noise propagation in limited enclosed space with non-compact bodies. In view of the scattering effect induced by solid boundaries, tailored green’s function methods are used to study the noise propagation. Frequency-domain integral equation is presented to calculate scattered noise under impedance boundary condition in enclosed space. At first, the scattered noise of circular cylinder with solid boundary condition is calculated to verify the validity of the present algorithm. Secondly, the impedance boundary condition is executed on the cylinder wall. Furthermore, the impedance boundary conditions are carried out on the boundaries of enclosed space. Numerical results demonstrate that the total noise drastically reduces in some areas with impedance boundary, but increases in other areas. The phenomenon is related with the cylinder radius, the location of sound sources and the scattering effect. In practical engineering problems, the impedance boundary should be applied locally according to the configuration.