Some results on energy-conserving lattice Boltzmann models

TL;DR

This paper develops a theoretical framework for energy-conserving lattice Boltzmann models, addressing the coupling of viscous and thermal waves, and demonstrates improved numerical performance in 2D schemes.

Contribution

It introduces a new theoretical approach based on partial equivalent equations to design lattice Boltzmann models that conserve energy and decouple viscous and thermal waves.

Findings

Numerical tests show improved wave decoupling.

The framework applies to multiple 2D schemes.

Main difficulties in previous models are overcome.

Abstract

We consider the problem of ''energy conserving'' lattice Boltzmann models. A major difficulty observed in previous studies is the coupling between the viscous and thermal waves even at moderate wave numbers. We propose a theoretical framework based founded on the knowledge of the partial equivalent equations of the lattice Boltzmann scheme at several orders of precision. With the help of linearized models (inviscid and dissipative advective acoustics and classical acoustics), we suggest natural sets of relations for the parameters of lattice Boltzmann schemes. The application is proposed for three two-dimensional schemes. Numerical test cases for simple linear and nonlinear waves establish that the main difficulty in the previous contributions can now be overcome.