CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM

Problem going from incompressible to compressible

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 28, 2013, 18:49
Default Problem going from incompressible to compressible
  #1
New Member
 
Ben Graves
Join Date: Dec 2012
Posts: 18
Rep Power: 14
bgraves is on a distinguished road
Hi everyone,

I am relatively new to OpenFOAM and in the past only ran simulations with the incompressible assumption. Now my research requires me to run without this assumption ie. compressible flow. I ran some simulations using simpleFoam and got good results. I am now trying to run the same simulations with rhoSimpleFoam. The simulation has zero pressure gradient and zero temperature gradient.

The first simulation is just flow over a flat plate at M=0.2 so the compressibility should only have a very small affect. However, when I run the simulations with rhoSimpleFoam I get an error that says "Maximum number of iterations has been exceeded." After looking through different forums I saw that this error is probably due to initial/boundary conditions. Since the simulation ran and produced good results running in incompressible mode, the only files that are different are for temperature, alphaT, and the thermophysicalProperties. I was wondering if anyone could look these over and make sure that I have not made some silly error.

Thanks,
-Ben

My boundary conditions for temperature and alphaT are shown below, as well as the thermophysicalProperties file
Code:
thermoType
{
    type            hePsiThermo;
    mixture         pureMixture;
    transport       sutherland;
    thermo          hConst;
    equationOfState perfectGas;
    specie          specie;
    energy          sensibleInternalEnergy;
}

mixture
{
    specie
    {
        nMoles      1;
        molWeight   28.9;
    }
    thermodynamics
    {
        Cp          1004.9;
        Hf          0;
    }
    transport
    {
        As          1.4792e-06;
        Ts          116;
    }
}
Temperature:
Code:
internalField   uniform 300;

boundaryField
{

    front
    {
        type            empty;
    }
    back
    {
        type            empty;
    }
    wall
    {
        type            zeroGradient;
    }
    symm
    {
        type            symmetryPlane;
    }
    top
    {
        type            fixedValue;
        value           $internalField;
    }
    inlet
    {
        type            fixedValue;
        value           $internalField;
    }
    outlet
    {
        type            inletOutlet;
        value           $internalField;
        inletValue      $internalField;
    }
}
alphaT:
Code:
internalField   uniform 0;

boundaryField
{
    front
    {
        type            empty;
    }
    back
    {
        type            empty;
    }
    wall
    {
        type            alphatWallFunction;
        value           uniform 0;
    }
    symm
    {
        type            symmetryPlane;

    }
    inlet
    {
        type            calculated;
        value           uniform 0;
    }
    top
    {
        type            calculated;
        value           uniform 0;
    }
    outlet
    {
        type            calculated;
        value           uniform 0;
    }
}
Thanks f
bgraves is offline   Reply With Quote

Old   September 3, 2013, 09:54
Default
  #2
Senior Member
 
Joachim Herb
Join Date: Sep 2010
Posts: 650
Rep Power: 22
jherb is on a distinguished road
I think your problem might be related to this: http://www.cfd-online.com/Forums/ope...tml#post425211

What are your U and p/p_rgh boundary conditions?

You could also try the (transient) pimple solver.
jherb is offline   Reply With Quote

Reply


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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
tank filling problem with compressible air Cle FLUENT 1 March 9, 2012 00:02
a problem of incompressible two phases(water and gas) with VOF Method zhangweisnoopy Main CFD Forum 9 August 12, 2011 09:25
incompressible to compressible cfdgeek Main CFD Forum 9 September 4, 2008 00:54
Convergence problem for compressible flow Saad Main CFD Forum 2 June 5, 2005 16:24
Compressible vs. Incompressible formulations Fernando Velasco Hurtado Main CFD Forum 3 January 7, 2000 17:51


All times are GMT -4. The time now is 23:28.