Lattice Boltzmann Equations-Based Model of the Convection Melt Flow Driven by the Combined Effects of Buoyancy, Surface Tension and Magnetic Body Forces with Heat Generation

2019 ◽  
Vol 390 ◽  
pp. 133-150
Author(s):  
F. Mechighel ◽  
S. Ben Aoua ◽  
S. Dost

The main topic of this paper is the development of a mathematical model, based on the Lattice Boltzmann equations (LBE), which is proposed for the simulation of the complex convective flow, held in an electrically conducting melt, driven by the combined action of buoyancy, surface-tension, and electromagnetic forces. The lattice Boltzmann method (LBM) is relatively novel and contrasts with the usual well-known methods to physical modeling in the domain of computational fluid dynamics (CFD). Indeed, the LBM describes the fluid (i.e. lattice fluid) at a microscopic level (molecular) and proposes models for the collision between molecules. The full continuum-level physics (i.e. the macroscopic hydrodynamic fields) is implicitly contained in the LB model. Indeed those macroscopic quantities are defined as moments of the so-called particle distribution functions. In the present work, a two-dimensions (2D) LBE-based model is developed to the simulation of convection melt flow driven by the combination of natural buoyancy, surface tension, and electromagnetic forces. The model is applied to numerical modeling of the problems of buoyancy, surface-tension, and electromagnetic driven convection melt flow in an enclosure. The melt system used has a low Prandtl number, which is appropriate to crystal growth melts.

Author(s):  
Gerasim Vladimirovich Krivovichev

Stability analysis of lattice Boltzmann equations (LBEs) on initial conditions for one-dimensional diffusion is performed. Stability of the solution of the Cauchy problem for the system of linear Bhatnaghar–Gross–Krook kinetic equations is demonstrated for the cases of D1Q2 and D1Q3 lattices. Stability of the scheme for D1Q2 lattice is analytically analyzed by the method of differential approximation. Stability of parametrical scheme is numerically investigated by von Neumann method in parameter space. As a result of numerical analysis, the correction of the hypothesis on transfer of stability conditions of the scheme for macroequation to the system of LBEs is demonstrated.


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