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-   -   About kinetic Theory in twoPhaseEulerFoam (http://www.cfd-online.com/Forums/openfoam-programming-development/98547-about-kinetic-theory-twophaseeulerfoam.html)

cheng1988sjtu March 13, 2012 11:31

About kinetic Theory in twoPhaseEulerFoam
 
Hi,

I'm using twoPhaseEulerFoam now to study sediment transport, and I'm courious about the kinetic theory part.

In the kineticTheory.C we can see that the dissipation due to inelastic collision has missed a term tr(D) as the laster term, has anyone evaluated how important is this term?

[QUOTE]// dissipation (Eq. 3.24, p.50)
volScalarField gammaCoeff
(
12.0*(1.0 - sqr(e_))*sqr(alpha_)*rhoa_*gs0_*(1.0/da_)*ThetaSqrt/sqrtPi
);
/QUOTE]

Also, the J2 term, that is the fluctuation energy production due to fluid-particle slip, does anyone know the original paper that propose this formula?

[QUOTE]volScalarField J2
(
0.25*sqr(betaPrim)*da_*sqr(Ur)
/(max(alpha_, scalar(1e-6))*rhoa_*sqrtPi*(ThetaSqrt + TsmallSqrt))
);/QUOTE]

and the last and the most important question is that, the 'pa' and 'tau' in kinetic theory is really alpha*pa or just pa, since it's wierd that it does not have alpha in front of it, while in UaEqn, the pa is directly added as normal pressure ( solved in pEqn). the question is , in pEqn, we should add pa or (pa/alpha) ?

in pEqn:
[QUOTE]if (kineticTheory.on())
{
phiDraga -= rUaAf*fvc::snGrad(kineticTheory.pa()/rhoa)*mesh.magSf();
}
/QUOTE]

Thank you very much!

cheng1988sjtu March 13, 2012 11:34

Reference ?
 
BTW, could anyone be kind enough to tell me where the reference of this kinetic theory is, since it has some comments in the code, however, I really don't know what they are referring to, Thanks!

Fine October 17, 2014 09:38

Berend van Wachem phd thesis. I got the full document by simply googling: Van Wachem phd thesis TUDelft. Kinetic theory for particles starts at page 78.

openfoammaofnepo April 8, 2016 16:32

Dear Charlie,

For this kinetic theory model, is it possible to use it as the particle phase LES model? Thanks. Did you have the experinece for that?

[QUOTE=cheng1988sjtu;349196]Hi,

I'm using twoPhaseEulerFoam now to study sediment transport, and I'm courious about the kinetic theory part.

In the kineticTheory.C we can see that the dissipation due to inelastic collision has missed a term tr(D) as the laster term, has anyone evaluated how important is this term?

[QUOTE]// dissipation (Eq. 3.24, p.50)
volScalarField gammaCoeff
(
12.0*(1.0 - sqr(e_))*sqr(alpha_)*rhoa_*gs0_*(1.0/da_)*ThetaSqrt/sqrtPi
);
/QUOTE]

Also, the J2 term, that is the fluctuation energy production due to fluid-particle slip, does anyone know the original paper that propose this formula?

[QUOTE]volScalarField J2
(
0.25*sqr(betaPrim)*da_*sqr(Ur)
/(max(alpha_, scalar(1e-6))*rhoa_*sqrtPi*(ThetaSqrt + TsmallSqrt))
);/QUOTE]

and the last and the most important question is that, the 'pa' and 'tau' in kinetic theory is really alpha*pa or just pa, since it's wierd that it does not have alpha in front of it, while in UaEqn, the pa is directly added as normal pressure ( solved in pEqn). the question is , in pEqn, we should add pa or (pa/alpha) ?

in pEqn:
Quote:

if (kineticTheory.on())
{
phiDraga -= rUaAf*fvc::snGrad(kineticTheory.pa()/rhoa)*mesh.magSf();
}
/QUOTE]

Thank you very much!


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