BEM for the prediction of standardized scattering and diffusion coefficients of diffusers

Ando Randrianoelina , Maarten Hornikx , Renz van Luxemburg , Stef van Eijndhoven , Azar Dastouri

For the prediction of the scattering and diffusion coefficients of acoustic diffusers, a computational method is used based on the measurement methods as prescribed in standards ISO 17497-1 and AES-4id-200. The numerical calculations concern a 2D implementation of the Boundary Element Method (BEM) in the frequency domain. The modelling approach aimed at reproducing the standardized measurement conditions as well as minimizing computational times. Modelling of the diffusion coefficient is mainly based on geometrical constraints from the standards. The prediction of the scattering coefficient requires to model physical processes during measurements, namely, the diffuse sound field and the specularly reflected energy. Also, the following computational aspects were considered: mesh density and required number of frequencies for broadband predictions, and use of separate and simultaneous sound sources. With the simulation method developed, the scattering and diffusion coefficients as well as the directivity patterns of a Schroeder diffuser and an undulated surface industrially manufactured have been computed.

Mots clés: BEM; scattering coefficient; simulation; diffusion coefficient

Domaines: Acoustique [physics.class-ph]

Ando Randrianoelina, Maarten Hornikx, Renz van Luxemburg, Stef van Eijndhoven, Azar Dastouri. BEM for the prediction of standardized scattering and diffusion coefficients of diffusers. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00811379⟩