Good news about airfoil and OpenFoam

Posted February 20, 2013 at 03:42 by skeptik

So, at the end of the testing OpenFOAM/simpleFoam, i get:

NACA23012
U=21.3, Re=0.44e6,

LowRe case, LaunderSharmaKE:
1. OF 1.7 cannot solve the case with kEpsilon on hex+tetra 2D mesh. It just crashes.

2. There are a lots of details when you use LowRe LSkEps model, you need lots of iteration, lots of interpolation data to provide better accuracy.

3. People invented k-omega for different flows near the walls. And better one - kOmega SST. So use it. You can use kEpsilon in CFX, just for fun, but in OpenFOAM it's not so easy.

Click image for larger version

Name: kEpsilon_lowRe.png
Views: 1199
Size: 36.3 KB
ID: 120

This good results obtained for a mesh witn yPlus not more than 10 (so it's not a proper mesh for LowRe). It utilized pure tri mesh (2D), hybrid mesh with quad and tri elements caused solver crash.

Posted in Uncategorized

Views 2516 Comments 4

« Prev Main Next »

Total Comments 4

Comments

	ok I understand ....... I am sumulating the flow over naca23012 and it is a pain in the ass getting the the solution to converge......I am using wall functions and a High Re 3*e06........I am interested to know about you fvschemes and fvsolutions that you used... I will appreciate that. Many thanks
	Posted March 19, 2013 at 16:05 by andrei.cimpoeru

Quote:

Originally Posted by andrei.cimpoeru

ok I understand ....... I am sumulating the flow over naca23012 and it is a pain in the ass getting the the solution to converge......I am using wall functions and a High Re 3*e06........I am interested to know about you fvschemes and fvsolutions that you used...
I will appreciate that.

Many thanks

i did not care about convergence cause i have an experimental results to validate my simulation's results.
If you have coarse mesh, the convergence could be really bad.

In addition fvSchemes and fvSolutions

Code:

ddtSchemes
{
    default         steadyState;
}

gradSchemes
{
    default         Gauss linear;
    grad(p)         Gauss linear;
    //grad(U)         Gauss linear;
    grad(U)         cellLimited Gauss linear 1;
}

divSchemes
{
    default         none;
//    div(phi,U)      Gauss upwind;
    div(phi,U)      Gauss linearUpwindV Gauss linear;
    div(phi,k)      Gauss upwind;
    div(phi,epsilon) Gauss upwind;
    div(phi,R)      Gauss upwind;
    div(R)          Gauss linear;
    div(phi,nuTilda) Gauss upwind;
    div((nuEff*dev(grad(U).T()))) Gauss linear;
}

laplacianSchemes
{
    default         Gauss linear limited 0.5; //none;
/*    laplacian(nuEff,U) Gauss linear corrected;
    laplacian((1|A(U)),p) Gauss linear corrected;
    laplacian(DkEff,k) Gauss linear corrected;
    laplacian(DepsilonEff,epsilon) Gauss linear corrected;
    laplacian(DREff,R) Gauss linear corrected;
    laplacian(DnuTildaEff,nuTilda) Gauss linear corrected;*/
}

interpolationSchemes
{
    default         linear;
    interpolate(U)  linear;
}

snGradSchemes
{
    default         corrected;
}

fluxRequired
{
    default         no;
    p               ;
}

Code:

solvers
{ 
    p
    {
        solver           GAMG;
        tolerance        1e-7;
        relTol           0.1;
        smoother         GaussSeidel;
        nPreSweeps       0;
        nPostSweeps      2;
        cacheAgglomeration on;
        agglomerator     faceAreaPair;
        nCellsInCoarsestLevel 10;
        mergeLevels      1;
    };

    U
    {
        solver           smoothSolver;
        smoother         GaussSeidel;
        tolerance        1e-8;
        relTol           0.1;
        nSweeps          1;
    };

    k
    {
        solver           smoothSolver;
        smoother         GaussSeidel;
        tolerance        1e-8;
        relTol           0.1;
        nSweeps          1;
        maxIter 100;
        minIter 1;
    };
   
    epsilon
    {
        solver           smoothSolver;
        smoother         GaussSeidel;
        tolerance        1e-8;
        relTol           0.1;
        nSweeps          1;
        maxIter 100;
        minIter 1;
    }

    R
    {
        solver           smoothSolver;
        smoother         GaussSeidel;
        tolerance        1e-8;
        relTol           0.1;
        nSweeps          1;
        maxIter 100;
        minIter 1;
    }

    nuTilda
    {
        solver           smoothSolver;
        smoother         GaussSeidel;
        tolerance        1e-8;
        relTol           0.1;
        nSweeps          1;
        maxIter 100;
        minIter 1;
    }
}

SIMPLE
{
    nNonOrthogonalCorrectors 4;
    pRefCell        0;
    pRefValue       0;
    
    residualControl
    {
        p               1e-5;
        U               1e-5;
        "(k|omega)"     1e-5;
    }
}

relaxationFactors
{
    p               0.3;
    U               0.5;
    k               0.7;
    epsilon         0.7;
    R               0.7;
    nuTilda         0.7;
}

Posted March 21, 2013 at 06:03 by skeptik skeptik is offline

	Hi Ilya, Do You have any experience with airfoil LES and Fv schemes and Fv solutions for Airfoil LES Thanks, Hasan K.J
	Posted November 15, 2013 at 14:44 by Alhasan

	Quote: Originally Posted by Alhasan Hi Ilya, Do You have any experience with airfoil LES and Fv schemes and Fv solutions for Airfoil LES Thanks, Hasan K.J I have no experience. But i try to simulate wing in tube. I know few good books about LES but only on russian.
	Posted November 16, 2013 at 17:07 by skeptik

Archive
< December 2024
Su	Mo	Tu	We	Th	Fr	Sa
24	25	26	27	28	29	30
1	2	3	4	5	6	7
8	9	10	11	12	13	14
15	16	17	18	19	20	21
22	23	24	25	26	27	28
29	30	31	1	2	3	4

CFD Online Discussion Forum Message

Cancel Changes