Numerical Stabilisation of the Lattice Boltzmann method for higher Reynolds number fluid

摘要

In this article, schemes of numerical stabilisation for a thermal multiphase Lattice Boltzmann Method are presented. As the model used is fully described in [6], it has been found unworth to re-introduce it in this work. In this paper, we give techniques to widen its compatibility range. Application to real thermal flow using LBM is usually limited to low value for Reynolds and Peclet numbers if the simulation is to be completed with reasonable computational ressources. Furthermore, the Prandtl number has to be kept close to unity. Similar problems occur when components have different viscosities. A new method that uses a percomponent grid with two seperate lattices for dynamics and thermal equations is introduced. Different grid resolutions should be used when components have important differences in viscosity, as well as when a component has higher Prandtl number. In order to keep reasonable need in computational resources, dynamic mesh refinement is used, and validated in the case of the increase of Reynolds number for isothermal case. The effect of the improved lattice on numerical stability and accuracy of the results are discussed. The decrease in need for computational resources is shown. A comparison between multiple relaxation scheme and single relaxation is shown, in terms of atteignable Reynolds number.