Title: Hybrid MD-continuum Simulation Methodology with Capability of Handling Two-Phase Flows
Presenter: Kasra Fattah-Hesary
Affiliation: Louisiana State University
Abstract: A coupled CFD-MD scheme for simulating multi-scale (micro- and nano-) fluidic systems has been further developed. The coupling process involves three domains i.e. CFD, MD and an overlap hybrid region. A commercial continuum code, ANSYS/FLUENT is employed for the continuum part of the simulation, and LAMMPS is adopted for the MD part. Coupling schemes and data interfaces are implemented in ANSYS/FLUENT using its User Defined Function (UDF) capability. In the overlap region a file-based information exchange method is applied between atomistic and continuum fluidic information to define boundary conditions for the continuum region and the appropriate constraint for the atomistic one. The coupling is applied to a one-phase plane Couette flow where the fluid-solid interface is modeled at molecular level and by choosing suitable fluid-solid interaction parameters, the results are validated by comparing with analytical solution. Then, we study the physics of fluid-fluid planar interfaces under shear by modeling an atomistic binary liquid Couette flow to set the stage for applying the hybrid scheme to multiphase-multiscale systems. Discrepancies between available semi-analytic solution and atomistic results in two-phase simulation are explained by interfacial viscosity.