Merge branch 'master' of https://github.com/AMReX-Codes/MFIX-Exa

# MFIX-Exa

This is the public face of the MFiX-Exa project.

The code for now lives at NETL; instructions for how to get access to the code will be given below.

The code for now lives at NETL; instructions for how to get access to the code

will be given below.

This repo is designed to host the documentation, gallery of results, etc.

## Editing

Do not push any edits to the `gh-pages` branch as these will be overwritten.

Instead, commit your changes to the `master` branch, and the `gh-pages` branch

will be updated automatially a few minutes later. The documentation source is

in `docs/source/` and the html source for the cover page is in `docs/webroot/`.

.. role:: cpp(code)

   :language: c++

.. _sec:particle-basics:

Particle Basics

===============

In MFiXi-Exa, particles are managed by the :cpp:`MFIXParticleContainer` class.

This class is derived from AMReX's :cpp:`NeighbourParticleContainer` and

handles all of the particle data. Most importantly,

:cpp:`MFIXParticleContainer` also provides the functions for solving the

particle dynamics (based on particle-particle, particle-fluid, and

particle-wall forces). Most importantly, :cpp:`MFIXParticleContainer` also

provides the functions for solving the particle dynamics (based on

particle-particle, particle-fluid, and particle-wall forces).

Particle Dynamics

-----------------

.. role:: cpp(code)

   :language: c++

.. _sec:particle-fluid:

Particle/Fluid Interactions

===========================

A standard :cpp:`mfix_level::Evolve` step looks like this (for brevity, we are

omitting some details here):

.. highlight:: c++

::

    // Calculate particle volume fraction:

    mfix_calc_volume_fraction(lev, sum_vol)

    // Eolve fluid

    if ( use_proj_method )

        EvolveFluidProjection(lev, nstep, dt, ...)

    else

        EvolveFluidSimple(lev, nstep, dt, ...)

    // Apply fluid drag force on particles

    mfix_calc_drag_particle(lev)

    // Move particles (using forces acting on particles)

    pc -> EvolveParticles(lev, nstep, dt ...)

Here, ``lev`` represents the AMR level, and ``pc`` is a pointer to a

:cpp:`MFIXParticleContainer` instance.

Particle/Wall Interactions

==========================

Particles

=========

MFiX-Exa supports solid particles which are immersed in the fluid. In the

future particles can be implemented using the immersed-boundary method (and

hence these IBM-particles can support non-spherical shapes, and special

hydrodynamical and chemical interactions). But for now, particles are

spherical, with approximate fluid-particle interactions. The main consequence

of this approximation is that particles should not be bigger than the fluid

grid resolution.

Particles interact with container walls (implemented using AMReX's

Embedded-Boundary functionality) using a level-set constructed from the signed

closest distance function at the beginning of the simulation.

Refer to the subsequent sections for details on the implementation of the

particle-particle, particle-fluid, and particle-wall interactions.

.. toctree::

   :maxdepth: 1

   :caption: Contents:

   ParticleBasics

   ParticleFuild

   ParticleWalls