Prediction of sound absorption in rigid porous media with the lattice Boltzmann method

• Published in: Journal of physics. A, Mathematical and theoretical Vol. 49; no. 6; pp. 65501 - 65513
• Main Authors: Silva, Andrey Ricardo da, Mareze, Paulo, Brandão, Eric
• Format: Journal Article
• Language: English
• Published: IOP Publishing 12.02.2016
• Subjects: lattice Boltzmann method; porous media; sound absorption
• ISSN: 1751-8113; 1751-8121
• DOI: 10.1088/1751-8113/49/6/065501

In this work, sound absorption phenomena associated with the viscous shear stress within rigid porous media is investigated with a simple isothermal lattice Boltzmann BGK model. Simulations are conducted for different macroscopic material properties such as sample thickness and porosity and the results are compared with the exact analytical solution for materials with slit-like structure in terms of acoustic impedance and sound absorption coefficient. The numerical results agree very well with the exact solution, particularly for the sound absorption coefficient. The small deviations found in the low frequency limit for the real part of the acoustic impedance are attributed to the ratio between the thicknesses of the slit and the viscous boundary layer. The results suggest that the lattice Boltzmann method can be a very compelling numerical tool for simulating viscous sound absorption phenomena in the time domain, particularly due to its computational simplicity when compared to traditional continuum based techniques.