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

simpleFoam /water in pipes/ how to obtain and tune the solution?

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

Reply
 
LinkBack Thread Tools Display Modes
Old   March 29, 2012, 10:40
Default simpleFoam /water in pipes/ how to obtain and tune the solution?
  #1
New Member
 
soonic's Avatar
 
Peter
Join Date: Apr 2010
Location: Brno, Czech Republic
Posts: 24
Rep Power: 7
soonic is on a distinguished road
Send a message via ICQ to soonic Send a message via AIM to soonic Send a message via Skype™ to soonic
Dont know how to hide or delete this for now, but i found mismatched BC. But maybe I will need help later. Thanks for visit.

Hello,

I am solving water flowing in pipe in steadyState by simpleFoam. I have Re~20000. Velocities 12m/s. I am unable to converge with my case. I did a comparison of case with laminar vs. k-eps regime, and tetra vs. polyhedral mesh (produced by polyDualMesh from that tets). Could you help me to tune up fvSchemes and fv Solution, please ? Or is it grid or BC related issue ?


I have read and tried several ideas written on the forum but no big success. I also divided the case in solving bended knee only, T-juction only. They have converged, but now the solution blows up e.g. on k and epsilon bounding and time step continuity error at some point of computation. I would like to compute temperature fields later on, but I am unable to solve flow for now.

my case:


boundaries are like: green inlet (hot water); red outlet (hot water); red inlet(cold water); blue outlet(cold water). Hot outlet and cold inlet is the same diameter and mass flow.
Files from system folder are attached. CheckMesh for both meshes as well. BCs are in the end of post. Now I will show resiaduals. Maybe somebody knows what happens there.

Thank you



http://soonic.cesnak.org/cfd/lam_pol...b_polyTurb.png




p
Code:
internalField   uniform 0;

boundaryField
{
    inh
    {
         type            zeroGradient;
    }
    inc
    {
        type            zeroGradient;
    }    
    outh
    {
    type            fixedValue;
        value           uniform 0;
    }
    outc
    {
         type            zeroGradient;
    }
    stena
    {
        type            zeroGradient;
    }
U
Code:
internalField   uniform (0 0 0 );

boundaryField
{
    inh
    {
        type            fixedValue;
        value           uniform (0.504 0 0); //Value is half scaled for laminar case
    }
    outh
    {
        type            fixedValue;
        value           uniform (0 1.7654 0); //Value is half scaled for laminar case
    }
    inc
    {
        type            fixedValue;
        value           uniform (0 -1.7654 0); //Value is half scaled for laminar case
    }
    outc
    {
        type            zeroGradient;
    }
    stena
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }
}
k
Code:
internalField   uniform 0.004;

boundaryField
{
    inh
    {
        type            turbulentIntensityKineticEnergyInlet;
        intensity       0.04726;
        U               U;
        phi             phi;
        value           uniform 0.000852;
    }
    outh
    {
        type            turbulentIntensityKineticEnergyInlet;
        intensity       0.04229;
        U               U;
        phi             phi;
        value           uniform 0.00836;
    }
    inc
    {
        type            turbulentIntensityKineticEnergyInlet;
        intensity       0.04229;
        U               U;
        phi             phi;
        value           uniform 0.00836;
    }
    outc
    {
        type            zeroGradient;
    }
    stena
    {
        type            kqRWallFunction;
        value           uniform 0.001;
    }
epsilon
Code:
internalField   uniform 100;

boundaryField
{
    inh
    {
        type            turbulentMixingLengthDissipationRateInlet;
        mixingLength    0.034678;
        phi             phi;
        k               k;
        value           uniform 0.0001179;
    }
    outh
    {
        type            turbulentMixingLengthDissipationRateInlet;
        mixingLength    0.02407;
        phi             phi;
        k               k;
        value           uniform 0.0052217;
    }
    inc
    {
        type            turbulentMixingLengthDissipationRateInlet;
        mixingLength    0.02407;
        phi             phi;
        k               k;
        value           uniform 0.0052217;
    }
    outc
    {
        type            zeroGradient;
    }
    stena
    {
        type            epsilonWallFunction;
        value           uniform 0.001;
    }
}
Attached Files
File Type: txt checkMesh.poly.txt (2.9 KB, 4 views)
File Type: txt checkMesh.tet.txt (2.9 KB, 1 views)
File Type: txt fvSolution.txt (2.8 KB, 9 views)
File Type: txt fvSchemes.txt (2.0 KB, 9 views)

Last edited by soonic; March 29, 2012 at 14:30.
soonic 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



All times are GMT -4. The time now is 15:22.