Application of a ghost fluid approach for a thermal lattice Boltzmann method
In this paper, a ghost fluid (GF) method is utilized to propose a numerical approach to enhance the capability of thermal lattice Boltzmann method (TLBM) in dealing with complex geometries. A ghost fluid approach is imposed on a double-population thermal lattice Boltzmann method. A Cartesian grid handles the flow and the boundaries are imposed by a ghost fluid approach. The essence of this method is to decompose the unknown distribution functions into equilibrium and non-equilibrium parts at each ghost points. The major quantities are extrapolated from the image points to the corresponding ghost points to form the equilibrium parts. The non- equilibrium parts are then determined by using the bounce-back scheme. The method is relatively easy to apply, and second order accurate. There is no need to modify the original governing equations, and both Dirichlet and Neumann boundary conditions can be handled. The method is applied to Couette flow between two concentric circular cylinders, natural convection in a square cavity, natural convection in an annulus, and a forced convection in a lid-driven semi-circular cavity. The results obtained are generally in good agreement with that predicted by other theoretical and numerical efforts.
ghost fluid approach thermal lattice boltzmann method complex geometry fluid flow heat transfer