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Good news about airfoil and OpenFoam

Posted February 20, 2013 at 02:42 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.

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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.
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  1. Old Comment
    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
    permalink
    Posted March 19, 2013 at 16:05 by andrei.cimpoeru andrei.cimpoeru is offline
  2. Old Comment
    Quote:
    Originally Posted by andrei.cimpoeru View Comment
    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;
    }
    permalink
    Posted March 21, 2013 at 06:03 by skeptik skeptik is offline
  3. Old Comment
    Hi Ilya,

    Do You have any experience with airfoil LES and Fv schemes and Fv solutions for Airfoil LES

    Thanks,
    Hasan K.J
    permalink
    Posted November 15, 2013 at 13:44 by Alhasan Alhasan is offline
  4. Old Comment
    Quote:
    Originally Posted by Alhasan View Comment
    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.
    permalink
    Posted November 16, 2013 at 16:07 by skeptik skeptik is offline
 

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