3D MFS analysis of SPL reduction between coupled enclosures

摘要

3D sound wave propagation between two closed spaces is studied, using the Method of Fundamental Solutions (MFS). A numerical study of the separation element (a small opening or a homogeneous lightweight panel) between the two rooms is performed, in order to understand the influence of the position and geometry of this opening in the sound pressure level reduction curve at low and mid frequencies. Additionally, the coupling effect between the two acoustic spaces is analyzed, in order to better understand its importance when determining the sound reduction. Different boundary conditions are ascribed to the walls of these rooms, simulating both completely reflecting and partially absorbing surfaces. The numerical modelling was performed using a multi-domain formulation of the Method of Fundamental Solutions (MFS). The system is composed of two coupled rooms, limited by rigid or by absorbing walls, and separated by a thin wall (tending to null thickness) with a small opening. An experimental validation of the proposed model is presented, comparing its results with those found experimentally for a reduced-scale model. It important to note that, for such a configuration, a traditional single-domain approach using methods like the MFS or the BEM would lead to undetermined equation systems, and thus the proposed model makes use of a domain decomposition technique.