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

High-Re / Boundary Layers

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 31, 2011, 00:26
Question High-Re / Boundary Layers
  #1
New Member
 
Alexandre Rubel
Join Date: Dec 2010
Location: Launceston, Tasmania AUSTRALIA
Posts: 28
Rep Power: 15
alex_rubel is on a distinguished road
Hi Foamers,
I'm trying to solve directly the boundary layers for an High-Re flow around a submarine.
I'm doing steadyState simulation with the kOmegaSST model (this model gave me the best results with the wallFunctions for a yPlus=10 mesh, I attached the checkMesh)

Since I didn't get any results with my submarine and every simulation take time to solve or at least to give an indication about the convergence or not of the simulation, I create a simple sphere model to test different configuration and get faster results. I'm not actually looking for accuracy but for the convergence in a first time.

I made a Re similarity and set the model. First, is that ok ?

I already try all the possibility for k,omega and nut with the following schemes :

Code:
gradSchemes
{
    default         Gauss linear;
    grad(p)         Gauss linear;
    grad(U)         Gauss linear;
}

divSchemes
{
    default         none;
    div(phi,U)      Gauss upwind;
    div(phi,k)      Gauss upwind;
    div(phi,omega)  Gauss upwind;
    div((nuEff*dev(grad(U).T()))) Gauss linear;
}

laplacianSchemes
{
    default         Gauss linear corrected;

}
And all the simulation crashed after a few time step.
I'm curently running the same things with :

Quote:
gradSchemes
{
default Gauss linear;
grad(p) Gauss linear;
grad(U) Gauss linear;

}

divSchemes
{
default none;
div(phi,U) Gauss linearUpwindV Gauss linear;
div(phi,k) Gauss linearUpwind Gauss linear;
div(phi,omega) Gauss linearUpwind Gauss linear;
div((nuEff*dev(grad(U).T()))) Gauss linear;
}

laplacianSchemes
{
default Gauss linear corrected;
}
I'll continue exploring different scheme settings after.

Do you some advice about the better schemes to solve the boundary layers for High-Re flows ?
And about the better settings for k, omega and nut ?


For the moment I decided to keep the same fvSolution settings

Quote:
solvers
{
p
{
solver GAMG;
tolerance 1e-12;
relTol 0.05;
smoother GaussSeidel;
nPreSweeps 0;
nPostSweeps 2;
cacheAgglomeration true;
nCellsInCoarsestLevel 10;
agglomerator faceAreaPair;
mergeLevels 1;
};

U
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-10;
relTol 0.1;
nSweeps 1;
};

k
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-10;
relTol 0.1;
nSweeps 1;
};

omega
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-10;
relTol 0.1;
nSweeps 1;
};
}

SIMPLE
{
nNonOrthogonalCorrectors 0;
}

relaxationFactors
{
p 0.3;
U 0.7;
k 0.7;
omega 0.7;
}
But playing with the URF is option which I have to explore.

If you have some advice for that too it will help me ?

Can it help me to solve it with a transient model ?

If you need more details about the model please ask me.

Hope someone can help me
Attached Files
File Type: txt checkMesh.txt (2.6 KB, 9 views)
alex_rubel is offline   Reply With Quote

Reply

Tags
boundary layer, high re, komegasst, scheme


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
Wind turbine simulation Saturn CFX 60 July 17, 2024 06:45
[Gmsh] Import problem ARC OpenFOAM Meshing & Mesh Conversion 0 February 27, 2010 11:56
RPM in Wind Turbine Pankaj CFX 9 November 23, 2009 05:05
boundary layers on a thin wall tilman FLUENT 0 February 15, 2006 10:35
New topic on same subject - Flow around race car Tudor Miron CFX 15 April 2, 2004 07:18


All times are GMT -4. The time now is 19:41.