Numerical Analysis of Acoustic Wave Propagation in Enclosures via Lattice Boltzmann Method: Impact of Geometry, Viscosity, and Source Characteristics

This study investigates acoustic wave propagation in two-dimensional enclosures, addressing critical applications in noise mitigation, architectural acoustics, and medical imaging. Despite previous research, a detailed parametric analysis of wave interference, dissipation, and stability remains lacking. A direct lattice Boltzmann method framework models acoustic wave behavior, focusing on geometric configurations, medium viscosity, and source parameters. Two oscillating local sources generate waves, while two receivers capture density fluctuations. For accuracy, the model is validated against established numerical benchmarks. The effects of varying aspect ratios (AR = 1, 2, 3), viscosities (ϑ = 0.025, 0.05, 0.1), source amplitudes (ρ_a= 0.01, 0.02, 0.04), and frequencies (f = 1/20, 1/40, 1/80) are studied through the simulations. Key findings indicate that increasing the aspect ratio reduces sidewall reflections and enhances wave stability, resulting in minimal range variation (<1%). Higher viscosity attenuates wave propagation, leading to a range reduction of up to 36.23%. A greater source amplitude significantly extends the wave range by over 100%, highlighting its strong influence on wave propagation, whereas a lower frequency decreases the range by up to 30.43%. Furthermore, changes in viscosity and wave amplitude significantly affect acoustic density at the receivers. For instance, increasing viscosity from 0.05 to 0.1 results in a 68.73% reduction in acoustic density at receiver R_2, while increasing amplitude from 0.01 to 0.02 leads to a 99.98% increase in density at receiver R_1. These findings highlight linear and nonlinear interactions in wave propagation and can offer insights for improving acoustic system design with the lattice Boltzmann method.