Lattice Boltzmann simulations of the acoustic radiation from waveguides

Abstract

The application of the lattice Boltzmann method to evaluate the far-field normal mode radiation pattern from an unflanged cylindrical waveguide is considered in this paper. The parameters associated with the radiation process such as directivity factor, end correction and reflection coefficient are predicted and compared with the theory of inviscid normal mode radiation derived by Levine and Schwinger. The good agreement found between numerical and analytical results, as well as the ability to intrinsically resolve fluid dynamics and acoustics problems suggests that the lattice Boltzmann approach is a useful tool to predict complex phenomena involving duct acoustics, such as nonlinear dissipation and the interaction between the acoustic field and the presence of a mean flow.