|
[Sponsors] |
November 21, 2012, 12:52 |
multiphaseEulerFoam - UEqn
|
#1 |
Member
Join Date: Jun 2011
Posts: 42
Rep Power: 14 |
Hi,
I see that in mEF, the phase intensive formulation is not used. Instead we have the UEqn as: Code:
(scalar(1) + fluid.Cvm(phase)/phase.rho())* ( fvm::ddt(alpha, U) + fvm::div(phase.phiAlpha(), U) - fvm::Sp(fvc::ddt(alpha) + fvc::div(phase.phiAlpha()), U) ) - fvm::laplacian(alpha*nuEff, U) - fvc::div ( alpha*(nuEff*dev(T(fvc::grad(U))) /*- ((2.0/3.0)*I)*k*/), "div(Rc)" ) == - fvm::Sp(fluid.dragCoeff(phase, dragCoeffs())/phase.rho(), U) //- (alpha*phase.rho())*fluid.lift(phase) + (alpha/phase.rho())*fluid.Svm(phase) 1) why is the term ((2.0/3.0)*I)*k) commented out? 2) shouldn't it be alpha*(nuEff*dev(symm(fvc::grad(U))) /*- ((2.0/3.0)*I)*k*/), instead of alpha*(nuEff*dev(T(fvc::grad(U))) /*- ((2.0/3.0)*I)*k*/), Thanks |
|
November 22, 2012, 17:39 |
|
#2 |
Member
Join Date: Jun 2011
Posts: 42
Rep Power: 14 |
isn't this part:
Code:
- fvm::laplacian(alpha*nuEff, U) - fvc::div ( alpha*(nuEff*dev(T(fvc::grad(U))) /*- ((2.0/3.0)*I)*k*/), "div(Rc)" ) Code:
- fvc::div ( alpha*(nuEff*2*dev(symm(fvc::grad(U))) - ((2.0/3.0)*I)*k), "div(Rc)" ) |
|
November 26, 2012, 11:40 |
|
#3 |
Senior Member
Kent Wardle
Join Date: Mar 2009
Location: Illinois, USA
Posts: 219
Rep Power: 21 |
I can check into this, but I think the answer is that mEF was written with LES only in mind and is not set up for RAS turbulence at all.
-Kent |
|
December 18, 2012, 14:25 |
|
#4 |
New Member
Join Date: Mar 2012
Posts: 29
Rep Power: 14 |
hmm... This is weird. It this OF210 you are using? In OF211, it is formulated as follows:
Code:
UEqns.set ( phasei, new fvVectorMatrix ( fvm::ddt(alpha, U) + fvm::div(phase.phiAlpha(), U) - fvm::Sp(fvc::ddt(alpha) + fvc::div(phase.phiAlpha()), U) + (alpha/phase.rho())*fluid.Cvm(phase)* ( fvm::ddt(U) + fvm::div(phase.phi(), U) - fvm::Sp(fvc::div(phase.phi()), U) ) - fvm::laplacian(alpha*nuEff, U) - fvc::div ( alpha*(nuEff*dev(T(fvc::grad(U))) /*- ((2.0/3.0)*I)*k*/), "div(Rc)" ) == - fvm::Sp(fluid.dragCoeff(phase, dragCoeffs())/phase.rho(), U) //- (alpha*phase.rho())*fluid.lift(phase) + (alpha/phase.rho())*fluid.Svm(phase) - fvm::Sp ( slamDampCoeff *max ( mag(U.dimensionedInternalField()) - maxSlamVelocity, dimensionedScalar("U0", dimVelocity, 0) ) /pow(mesh.V(), 1.0/3.0), U ) ) ); Thanks, Yanxiang |
|
March 22, 2013, 05:34 |
|
#5 |
Member
Join Date: Jun 2011
Posts: 42
Rep Power: 14 |
I am bumping up this thread, but there is something strange with twoPhaseEulerFoam when I compare its code in OF2.0, OF2.1, and OF2.2
In OF2.0, there is the term with the turbulent kinetic energy in the definition of the reynolds stresses, as it should. see line 21 in (https://github.com/OpenFOAM/OpenFOAM...erFoam/UEqns.H) But this term is vanished in 2.1 and 2.2. see line 21 in (https://github.com/OpenFOAM/OpenFOAM...erFoam/UEqns.H) why is that? |
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
A question about UEqn sonicFoam | lfgmarc | OpenFOAM Programming & Development | 6 | February 1, 2015 16:49 |
solving the momentum equation in UEqn. | callahance | OpenFOAM | 2 | October 18, 2012 09:38 |
UEqn in cavitatingFoam | Alexanger | OpenFOAM Running, Solving & CFD | 0 | July 19, 2011 09:12 |
Source term problem in UEqn of simpleFoam | fisch | OpenFOAM Programming & Development | 1 | June 17, 2011 10:57 |
interFoam Ueqn | alvin11 | OpenFOAM | 2 | December 2, 2010 01:28 |