Entropic Lattice Boltzmann Method for Multiphase Flows

Abstract

A novel thermodynamically consistent lattice Boltzmann model that enables dynamical effects of two-phase fluids is developed. The key innovation is the application of the entropic lattice Boltzmann stabilization mechanism to control the dynamics at the liquid-vapor interface. This allows us to present a number of simulations of colliding droplets, including complex phenomena such as the formation of a stable lamella film. Excellent agreement of the simulation with recent experiments demonstrates the viability of the present approach to simulation of complex dynamic phenomena of multiphase fluids.

Drops bouncing off macro-textured superhydrophobic surfaces

“…The method was discussed in detail elsewhere [24][25][26]; a brief summary is given below. ELBM equation for the populations f i (x, t) of the discrete velocities v i , i = 1, .…”

“…We use the entropic lattice Boltzmann model (ELBM) for two-phase flows [24]. The method was discussed in detail elsewhere [24][25][26]; a brief summary is given below.…”

“…It is important to note that the model used here is free of an tuning parameters and case based modeling. The simulation algorithm including the liquid-vapor interactions and the fluid-solid interactions remain the same for collision of two droplets and also collision of a droplet with a flat or complex wall [24][25][26]. Such accurate and reliable simulations combined with novel analysis techniques can uncover the physics behind these droplet wall interactions and lead to the design, optimization and also discovery of new surfaces.…”

“…The recently introduced entropic lattice Boltzmann method (ELBM) for two-phase flows [24] is free of the aforementioned limitations and enables us to consider complex texture with the realistic geometry. First, the validity and the accuracy of the numerical simulations is established by comparing the simulation results with those recently observed by experiments for pancake bouncing on superhydrophobic surfaces in Ref [19] and interaction of a droplet with a flat surface.…”

Contactless prompt tumbling rebound of drops from a sublimating slope

“…To provide insight into the appearance of tumbling, we used the ELBM modeling approach [34], employing the Navier-Stokes equations for a two-phase fluid, where a van der Waals-type equation of state and Korteweg's stresses are implemented in the kinetic lattice Boltzmann setting of discrete velocity populations [35][36][37]. The impacting liquid was modeled as a drop on a superhydrophobic surface [38] with the contact angle θ = 180 • and partial slip at the wall (see Ref.…”