1. Numerical Simulation of Immiscible Multiphase Flows Using
Lattice Boltzmann Methods
ABSTRACT
Computational study of multiphase flows is an important topic that has attracted many researchers across the globe. Despite significant advances in the field, accurate and efficient modeling of complex fluid flows still poses a great challenge. The main difficulty is devising an accurate, and numerically stable, interface tracking method that can handle acute topological changes such as coalescence and breakup. The most popular interface tracking schemes, namely the volume-of-fluid, front-tracking, level-set, and phase-field methods, are all macroscopic models and therefore rely on the continuum assumption. Given that the interface between different fluids is on the order of nanometers, microscopic (or mesoscopic) approaches are more suitable. The Lattice Boltzmann Method (LBM) is a well-established mesoscopic scheme based on kinetic theory of dense fluids. The phase-field-based LBM is particularly advantageous in simulation of multiphase fluids with complex geometries, and in studying contact line dynamics.
In the first part of the talk, I will present a state-of-the-art LBM solver, which can be effectively equipped with an Adaptive Mesh Refinement (AMR) technique, for direct numerical simulation of multiphase flows. I will employ the proposed AMR-LBM to study a variety of multiphase flow phenomena that are of fundamental importance in fluid dynamics and engineering, such as Kelvin-Helmholtz instability, droplet splashing on a wet surface, coalescence of a liquid drop at a liquid-liquid interface, etc. I will also formulate curved boundary conditions for contact line motion within the diffuse-interface modeling framework and present some numerical simulations of drop impact dynamics on a superhydrophobic circular surface.
In the second part of the presentation, I will look into solute transport and multiphase flow in porous media. First I will study the effect of Péclet number on the breakthrough curves obtained from a passive scalar in a single-phase flow through a homogenous porous medium. Then I will show some preliminary results for CO2 sequestration in a heterogeneous porous micromodel
Tuesday, December 6, :00-12:00 noon DeBartolo Hall
Dr. Abbas Fakhari
Postdoctoral Research Associate
Department of Civil and Environmental Engineering and Earth Sciences
Notre Dame University
BIO
Abbas Fakhari is currently a Postdoctoral Research Associate in the Department of Civil and Environmental Engineering and Earth Sciences at Notre Dame under Dr. Diogo Bolster. He received his Ph.D. in Mechanical Engineering from the City College of New York in His doctoral research was focused on direct numerical simulation of multiphase flows, including droplet dynamics, breakup and coalescence, and shear-layer instabilities, using lattice Boltzmann methods and adaptive mesh refinement techniques. In addition to expanding his doctoral research, he is focused on modeling fate and transport in porous media and studying geologic CO2 sequestration through porous micromodels.