Two-dimensional Acoustic Analysis by Concentrated Mass Model

FDTD method and CIP method are used for an acoustic analysis in time domain. However, these methods do not take into account a sound attenuation from viscosity. In our study, we propose a concentrated mass model which consists of spring-mass-damper system to perform a two-dimensional acoustic analysis. The dampers of this model consider viscosity of air. In this paper, we derive mass, connecting springs, and connecting dampers. The characteristic of connecting spring is derived from the condition of adiabatic change of air, and the connecting damper is derived from the normal stress. To confirm the validity of the proposed model, the numerical results obtained by the concentrated mass model are compared with the theoretical value of a traveling wave, and with the theoretical value of the natural frequency. All numerical computational results agree very well with the theoretical values. Therefore, it is concluded that the proposed model is valid for the two-dimensional acoustic analysis.