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63 lines
2.2 KiB
HTML
63 lines
2.2 KiB
HTML
<HTML>
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<CENTER><A HREF = "http://www.cfdem.com">CFDEMproject WWW Site</A> - <A HREF = "CFDEMcoupling_Manual.html#comm">CFDEM Commands</A>
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<HR>
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<H3>voidfractionModel_dividedVoidFraction command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<P>Defined in couplingProperties dictionary.
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</P>
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<PRE>voidfractionModel divided;
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dividedProps
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{
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alphaMin number1;
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scaleUpVol number2;
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interpolation;
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weight number3;
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}
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</PRE>
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<UL><LI><I>number1</I> = mininmum limit for voidfraction
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<LI><I>number2</I> = diameter of the particle's representation is artificially increased according to <I>number2</I> * Vparticle, volume remains unaltered!
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<LI><I>interpolation</I> = flag to interpolate voidfraction to particle positions (normally off)
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<LI><I>number3</I> = scaling of the particle volume to account for porosity or agglomerations.
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</UL>
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<P><B>Examples:</B>
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</P>
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<PRE>voidfractionModel divided;
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dividedProps
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{
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alphaMin 0.2;
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scaleUpVol 1.0;
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weight 1.;
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}
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>The divided voidFraction model is supposed to be used when a particle (or it's representation) is in the size range of a CFD cell. Satellite points are used to divide the particle's volume to the touched cells.
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</P>
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<P>The region of influence of a particle can be increased artificially by "scaleUpVol", which blows up the particles, but keeps their volume (for voidfraction calculation) constant.
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</P>
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<P>The particle volume occupied in the CFD domain can be adjusted by the parameter "weight", using Vparticle=dsphere^3*pi/6*weight.
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</P>
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<P>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.
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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.
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</P>
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<P><B>Restrictions:</B> none.
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</P>
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<P><B>Related commands:</B>
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</P>
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<P><A HREF = "voidfractionModel.html">voidfractionModel</A>
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</P>
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</HTML>
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