CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Running, Solving & CFD

High diffusion in interFoam

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   January 24, 2013, 12:27
Default High diffusion in interFoam
  #1
Senior Member
 
Andrea Ferrari
Join Date: Dec 2010
Posts: 275
Rep Power: 7
Andrea_85 is on a distinguished road
Hi all,

i am simulating a meniscus that moves in capillary tubes of different shape with small contact angle (from 1 up to 30). I have observed a very large diffusion of the interface which sometimes leads to non-physical or not-expected results. I was wondering if i can limit diffusion without without touching cAlpha, which is set to 1 at the moment, maybe playing with schemes for convective terms. Which schemes can be used in interFoam to limit diffusion?

This is how my fvScheme looks like:
Code:
ddtSchemes
{
    default         Euler;
}

gradSchemes
{
    default         leastSquares;
//    grad(U)         Gauss linear;
//    grad(alpha1)    Gauss linear;
}

divSchemes
{
    div(rho*phi,U)  Gauss limitedLinearV 1;
    div(phi,alpha)  Gauss vanLeer;
    div(phirb,alpha) Gauss interfaceCompression;
}

laplacianSchemes
{
    default         Gauss linear corrected;
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    default         corrected;
}

fluxRequired
{
    default         no;
    p_rgh;
    pcorr;
    alpha1;
}
and fvSolution

Code:
solvers
{
    pcorr
    {
        solver          PCG;
        preconditioner  DIC;
        tolerance       1e-10;
        relTol          0;
    }

    p_rgh
    {
        solver          PCG;
        preconditioner  DIC;
        tolerance       1e-07;
        relTol          0.05;
    }

    p_rghFinal
    {
        solver          PCG;
        preconditioner  DIC;
        tolerance       1e-07;
        relTol          0;
    }

    U
    {
        solver          PBiCG;
        preconditioner  DILU;
        tolerance       1e-06;
        relTol          0;
    }
     UFinal
    {
        solver          PBiCG;
        preconditioner  DILU;
        tolerance       1e-06;
        relTol          0;
    }


PIMPLE
{
    momentumPredictor yes;
    nCorrectors     3;
    nNonOrthogonalCorrectors 1;
    nAlphaCorr      1;
    nAlphaSubCycles 3;
    cAlpha          1;
}
and controlDict

Code:
application     interFoam;

startFrom       startTime;

startTime       0;

stopAt          endTime;

endTime         0.22;

deltaT          0.000000001;

writeControl    adjustableRunTime;

writeInterval   0.01;

purgeWrite      0;

writeFormat     ascii;

writePrecision  6;

writeCompression uncompressed;

timeFormat      general;

timePrecision   6;

runTimeModifiable yes;

adjustTimeStep  yes;

maxCo           0.1;
maxAlphaCo      0.1;

maxDeltaT       0.01;
thanks

andrea
Andrea_85 is offline   Reply With Quote

Old   January 24, 2013, 16:59
Default
  #2
Senior Member
 
akidess's Avatar
 
Anton Kidess
Join Date: May 2009
Location: Delft, Netherlands
Posts: 919
Rep Power: 17
akidess will become famous soon enough
Instead of vanLeer you can use MULES or SuperBee, both of which should be more compressive. Don't expect too much though.
__________________
*On twitter @akidTwit
*Spend as much time formulating your questions as you expect people to spend on their answer.
*Help define the OpenFOAM stackexchange Q&A site: http://area51.stackexchange.com/prop...oam-technology
akidess is offline   Reply With Quote

Old   January 31, 2013, 05:08
Default
  #3
Senior Member
 
Andrea Ferrari
Join Date: Dec 2010
Posts: 275
Rep Power: 7
Andrea_85 is on a distinguished road
Thanks Anton, i'll give them a try.

best

andrea
Andrea_85 is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Moving mesh Niklas Wikstrom (Wikstrom) OpenFOAM Running, Solving & CFD 122 June 15, 2014 06:20
Alternatives for InterFoam - High Viscosity Ratio Problem saba_saeb OpenFOAM 3 November 13, 2012 17:57
Non-physical alpha1 with interFoam and high contact angles steph79 OpenFOAM Running, Solving & CFD 7 November 6, 2012 05:17
InterFoam Artificially High Velocities andersson.j OpenFOAM Running, Solving & CFD 0 February 8, 2011 11:43
Multicomponent fluid Andrea CFX 2 October 11, 2004 05:12


All times are GMT -4. The time now is 07:49.