Author(s)

M. Tsutahara, A. Tamura, S. Tajiri & W. Long

Abstract

In this paper we present some applications of the finite difference lattice Boltzmann method (FDLBM) to direct simulations of fluid dynamic sound. The Arbitrary Lagrangian Eulerian formulation is introduced to FDLBM and the sounds emitted from moving bodies are successfully simulated. The two-particle model is used to simulate two-phase flows, and introducing a fluid elasticity the sound propagation inside the liquid is simulated. The sounds generated on the interface between the liquid and gas are also successfully simulated. Keywords: fluid dynamic sound, lattice Boltzmann method, Arbitrary Lagrangian Eulerian formulation, two-phase flow, under water sound. 1 Introduction The lattice Boltzmann method [1–6] is now a very powerful tool of computational fluid dynamics (CFD). This method is different from ordinary Navier-Stokes equations based CFD methods, and is based on the particle motions. However, mostly successful model so far is for incompressible fluids, but several models for thermal compressible models have been proposed including our model [7–13]. On the other hand, this method has great advantage to simulate multi-phase flows, because the interface is automatically determined in this method without special treatment [14–17]. We use a compressible fluid model of LBM and perform direct simulations of aerodynamic sound emitted from moving bodies using the arbitrary Lagrangian Eulerian formulation, especially the sound sources are detected. We also propose a new model for liquids considering the elasticity of liquid, and the sound speed propagating inside the liquid is correctly realized. A simulation of a water drop colliding the water surface and sound emission is performed.

Keywords

fluid dynamic sound, lattice Boltzmann method, Arbitrary Lagrangian Eulerian formulation, two-phase flow, under water sound.