Lattice Boltzmann simulation of the Rayleigh–Taylor Instability (RTI) during the mixing of the immiscible fluids

Abstract

The Lattice Boltzmann Method (LBM) was implemented to simulate the two-dimensional (2-D) Rayleigh–Taylor instability (RTI) during the mixing of the immiscible fluids. Two important parameters of the density and the viscosity as represented respectively by the Atwood and the Reynolds numbers were considered. In the calculation the density of two immiscible fluids was calculated by using the equation of state (EOS). In the present simulations, both Atwood and Reynolds numbers were varied in order to investigate the time variations of the interfacial behavior during RTI, the position of bubbles and spikes, and the horizontal average density. The results indicate that the Atwood number has a higher effect than the Reynolds number in the mixing process during RTI. The bubbles and spikes positions go farther in the displacement with the increase of both Reynolds and Atwood numbers. Moreover, the increase of both Reynolds and Atwood numbers accelerate the mixing process during RTI.