Lattice Boltzmann simulations of phase-separating flows at large density ratios: the case of doubly-attractive pseudo-potentials

It is shown that the cooperation between short and mid range attraction in Lattice Boltzmann (LB) models with multi-range pseudo-potentials, permits the achievement of phase-separation at liquid/vapor density ratios in excess of 1 : 500, nearly an order of magnitude above the current limits of standard single-range LB models. Inspection of the density configurations reveals that this favourable behaviour results from a sizeable reduction of spurious currents near the liquid/vapour interface. The aforementioned enhancement of the density ratio is obtained at virtually the same computational cost of the standard single-range models. As a consequence, the present results may open the way to a broader spectrum of LB applications, involving the dynamics of complex phase-separating flows with large density ratios.