Lattice Boltzmann Simulation for Sloshing in a Circular Tank under Microgravity Conditions

Abstract

We attempt to apply a Lattice Boltzmann Method to sloshing analysis in a circular tank under microgravity conditions. Numerical simulations are effective tools to predict sloshing phenomena in a propellant tank in microgravity conditions. In order to realize the analysis of such phenomena, a numerical method that conserves the fluid volume accurately, copes with large deformation of the gas-liquid interface, and properly expresses the surface tension and wettability is required. To satisfy these requirements, we have focused on the method combining the Lattice Boltzmann Method (LBM) and Phase Field Method (PFM). The Conservative-Allen-Cahn (CA-C) equation is employed as the interface tracking equation, and the velocity-based LBM is employed as the Lattice Boltzmann Method to compute the pressure and velocity fields. In addition, the Interpolated Bounce Back is applied for the no-slip condition around the curved surfaces, and the cubic boundary condition is applied for the wetting condition. It is verified that the present method has good volume conservation and can express wettability with high accuracy. Finally, using the present method, several analyses of sloshing phenomena in a circular tank under microgravity conditions have been carried out, and it is confirmed that the phenomena varies significantly depending on the equilibrium contact angle.