## Title: Dense gas flow simulations in ultra-tight confinement ##
Authors:  Qiang Sheng, Livio Gibelli, Jun Li, Matthew K. Borg and Yonghao Zhang

This data folder contains LAMMPS input files for molecular dynamics (MD) simulations and a new fix_command for use in LAMMPS. MD simulations are run with LAMMPS version 16 Mar 2018 (https://lammps.sandia.gov).

File descriptions:

Two folders are contained. The folder (diffusiveBoundaryCondition) gives a file for the implementation of diffusive boundary conditions used in the present work, while the folder (exampleCase) gives an example case with R=5, reduced density =0.2 and reduced force=0.01 (see paper for terminology)

In the folder (diffusiveBoundaryCondition):

fix_wall_reflect.cpp : this is a new fix code that implement diffusive boundary conditions. It is a C++ file that replaces the reflective boundary called fix wall/reflect in LAMMPS, with altered reflections using the standard Maxwell diffuse equations. To use the new ‘fix’, add it to your LAMMPS distribution and replace the original fix wall/reflect, then compile again. The usage is the same as the original one, as shown in the manual of LAMMPS: https://lammps.sandia.gov/doc/fix_wall_reflect.html. This code only allows reflections to the z-direction of a domain and for fixed momentum accommodation coefficient and temperature.


In the folder (exampleCase):

main.in	: this is the LAMMPS input script for the example case, which contains generation of gas molecules, initialization of molecular velocities, relaxation to equilibrium and the steady gas flows simulations. This file is opened by a standard text editor.

averageChunk-profile.txt: is the output of profiles across the channel during the simulations. This file is opened by a standard text editor.


The folder (postprocess) contains the code for post-processing the results and the code for figure plotting via Python.