Modeling 3D thin sound-absorbing barriers using a dual formulation based on the boundary element method

This study implements a three-dimensional (3D) dual boundary element method formulation to simulate the propagation of sound generated by point pressure sources in the presence of a 3D thin acoustic barrier, placed on reflective ground and having a locally reactive surface. The formulation applies the classical boundary integral equation of the boundary element method (BEM) to one surface of the barrier and a normal derivative integral equation to the other surfaces. The sound absorption at the surface of the barrier is ascribed by applying an impedance boundary condition. Only the boundary of the barrier is discretized by boundary elements. The influence of the reflective ground is taken into account by using the fundamental solutions for a semi-infinite acoustic space and using the image source technique. The formulation is established in the frequency domain. After verification of the proposed model, different numerical applications are simulated to illustrate the applicability and usefulness of the proposed approaches. Time domain results and frequency domain results are analyzed. The number of barriers, the proximity of a vertical reflection plane and the sound absorption coefficient are the variables analyzed.