68 lines
2.0 KiB
Plaintext
68 lines
2.0 KiB
Plaintext
"CFDEMproject Website"_lws - "Main Page"_main :c
|
|
|
|
:link(lws,http://www.cfdem.com)
|
|
:link(main,CFDEMcoupling_Manual.html)
|
|
|
|
:line
|
|
|
|
voidfractionModel divided command :h3
|
|
|
|
[Syntax:]
|
|
|
|
Defined in "couplingProperties"_CFDEMcoupling_dicts.html#couplingProperties
|
|
dictionary.
|
|
|
|
voidfractionModel divided;
|
|
dividedProps
|
|
\{
|
|
alphaMin number1;
|
|
interpolation;
|
|
weight number2;
|
|
porosity number3;
|
|
\} :pre
|
|
|
|
{number1} = minimum limit for voidfraction :ulb,l
|
|
{interpolation} = flag to interpolate voidfraction to particle positions (normally off) :l
|
|
{number2} = (optional) scaling of the particle volume to account for porosity or agglomerations. :l
|
|
{number3} = (optional) diameter of the particle's representation is artificially increased according to {number2} * Vparticle, volume remains unaltered! :l
|
|
:ule
|
|
|
|
[Examples:]
|
|
|
|
voidfractionModel divided;
|
|
dividedProps
|
|
\{
|
|
alphaMin 0.2;
|
|
\} :pre
|
|
|
|
[Description:]
|
|
|
|
The {divided} voidFraction model is supposed to be used when a particle (or its
|
|
representation) is in the size range of a CFD cell. Satellite points are used to
|
|
divide the particle's volume to the touched cells.
|
|
|
|
The region of influence of a particle can be increased artificially by
|
|
"porosity", which blows up the particles, but keeps their volume (for
|
|
voidfraction calculation) constant.
|
|
|
|
The particle volume occupied in the CFD domain can be adjusted by the parameter
|
|
"weight", using Vparticle=dsphere^3*pi/6*weight.
|
|
|
|
In the basic implementation of solvers, the void fraction is calculated based on
|
|
all particles. Depending on the solver used, the void fraction calculation is
|
|
also performed for a certain type of particles.
|
|
The void fraction calculation is based on a three-step approach (reset, set and
|
|
interpolate), i.e. the void fraction is time interpolated from a previous and a
|
|
next void fraction field. Appropriate names for these fields have to be
|
|
specified in the sub-dictionaries voidFracFieldNamesPrev and
|
|
voidFracFieldNamesNext in the couplingProperties dictionary.
|
|
|
|
[Restrictions:]
|
|
|
|
none
|
|
|
|
[Related commands:]
|
|
|
|
"voidfractionModel"_voidFractionModel.html
|
|
|