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IDProjectCategoryView StatusLast Update
0001291OpenFOAMBugpublic2014-05-16 13:19
Reporterprojectionist Assigned Tohenry  
PrioritynormalSeverityminorReproducibilityalways
Status resolvedResolutionfixed 
PlatformLinuxOSUbuntuOS Version12.04
Summary0001291: [Diameter model IATE] sign error
DescriptionIn the transport equation of the IATE diameter model of twoPhaseEulerFoam there seems to be a wrong sign on the right hand side. In the code of OpenFOAM the right hand side of the transport equation for kappa has a negative sign.

When looking up the interfacial area transport equation in (Yao and Morel, 2004) and (Ishii, Kim and Kelly, 2005) the right hand side has no negative sign.

OpenFOAM uses the interfacial curvature (kappa) which corresponds to the interfacial area concentration (a_i) as follows a_i = alpha*kappa with the gas phase volume fraction alpha.

Maybe, I made a mistake when deriving OpenFOAM's kappa equation from the transport equation of the interfacial aera concentration of the referred literature [Ishii et al. 2005, Eq. 15; Yao and Morel, 2004; Eq. 7].
If my derivation is correct the negative sign in ( - fvm::SuSp(R, kappai_) ) is wrong.
Steps To Reproduce    // Initialise the accumulated source term to the dilatation effect
    volScalarField R
    (
        (
            (2.0/3.0)
           /max
            (
                fvc::average(phase_ + phase_.oldTime()),
                residualAlpha_
            )
        )
       *(fvc::ddt(phase_) + fvc::div(phase_.alphaPhi()))
    );

    // Construct the interfacial curvature equation
    fvScalarMatrix kappaiEqn
    (
        fvm::ddt(kappai_) + fvm::div(phase_.phi(), kappai_)
      - fvm::Sp(fvc::div(phase_.phi()), kappai_)
     ==
      - fvm::SuSp(R, kappai_)
    );
TagsNo tags attached.

Activities

henry

2014-05-13 15:40

manager   ~0003057

The sign is correct but the constant is not. Combining the

fvc::ddt(phase_) + fvc::div(phase_.alphaPhi())

from the LHS with the

(2/3)*(fvc::ddt(phase_) + fvc::div(phase_.alphaPhi()))

on the RHS

results in

-(1/3)*(fvc::ddt(phase_) + fvc::div(phase_.alphaPhi()))

on the RHS, do you agree?

henry

2014-05-16 13:19

manager   ~0003060

Resolved by commit 979da78e599961c304299c2d077100d03fcd51ce

Issue History

Date Modified Username Field Change
2014-05-12 16:59 projectionist New Issue
2014-05-13 15:40 henry Note Added: 0003057
2014-05-16 13:19 henry Note Added: 0003060
2014-05-16 13:19 henry Status new => resolved
2014-05-16 13:19 henry Resolution open => fixed
2014-05-16 13:19 henry Assigned To => henry