2D Airfoil do not converge - pressure residuals do not go below 1e-4

rinaldialberto · November 15, 2019, 11:53

Hi there,

I am running a 2D simulation on a MH32 airfoil.
I generated an O-Grid mesh using construct2D and then converted using plot3DToFoam. The mesh diameter is 30x the chord length, y+<1 and max skewness < 30deg.

I'd like to solve it with simpleFoam, modelling turbulence using transient kOmegaSSTLM.

The simulation gives wrong results for Cd, Cl, Cm, Cp.
Is it a convergence problem?
Are the settings I am using correct?

I attach my codes.

Regards
Alberto

U:

Code:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    location    "0";
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#include        "include/initialConditions"

dimensions      [0 1 -1 0 0 0 0];

internalField   uniform $flowVelocity;

boundaryField
{
    side
	{
		type  				inletOutlet;
		inletValue 			$internalField;
		value 				$internalField;
	}

    profile
    {
        type            noSlip;
    }


    #include "include/frontBackTopBottomPatches"
}


// ************************************************************************* //

p:

Code:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    object      p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#include        "include/initialConditions"

dimensions      [0 2 -2 0 0 0 0];

internalField   uniform $pressure;

boundaryField
{
    side
    {
		type  				outletInlet;
		outletValue 		$internalField;
		value 				$internalField;
    }

    profile
    {
        type            zeroGradient;
    }


    #include "include/frontBackTopBottomPatches"
}

// ************************************************************************* //

k:

Code:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    object      k;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#include        "include/initialConditions"

dimensions      [0 2 -2 0 0 0 0];

internalField   uniform $turbulentKE;

boundaryField
{
    side
	{
		type			turbulentIntensityKineticEnergyInlet;			//	type  				inletOutlet;
		intensity		0.01;											//	inletValue 			$internalField;
		value			$internalField;									//	value 				$internalField;
	}


    profile
    {
        type            fixedValue;
        value           uniform 0;		//1e-15
    }

    #include "include/frontBackTopBottomPatches"
	
}


// ************************************************************************* //

omega:

Code:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    object      omega;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#include        "include/initialConditions"

dimensions      [0 0 -1 0 0 0 0];

internalField   uniform $turbulentOmega;

boundaryField
{
    side
	{
		type			turbulentMixingLengthFrequencyInlet;	// type  				inletOutlet;
		mixingLength	1;										// inletValue 			$internalField;
		value			$internalField;							// value 				$internalField;
	}

    profile
    {
        type            omegaWallFunction;
        value           $internalField;
    }

    #include "include/frontBackTopBottomPatches"
}


// ************************************************************************* //

nut:

Code:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    location    "0";
    object      nut;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 2 -1 0 0 0 0];

internalField   uniform 0;

boundaryField
{
    profile
    {
        type  	fixedValue;
		value 	uniform 0;
    }

    "(top|bottom|side)"
    {
        type            calculated;
        value           uniform 0;
    }
}


// ************************************************************************* //

gammaInt:

Code:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    location    "0";
    object      gammaInt;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 0 0 0 0 0 0];
#include        "include/initialConditions"

internalField   uniform $gammaInt;

boundaryField
{
    side
	{
		type  				inletOutlet;
		inletValue 			$internalField;
		value 				$internalField;
	}

    profile
    {
        type            zeroGradient;
    }


    #include "include/frontBackTopBottomPatches"
}

// ************************************************************************* //

ReTheta:

Code:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    location    "0";
    object      ReThetat;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 0 0 0 0 0 0];
#include        "include/initialConditions"

internalField   uniform $reTheta;

boundaryField
{
    side
	{
		type  				inletOutlet;
		inletValue 			$internalField;
		value 				$internalField;
	}

    profile
    {
        type           		zeroGradient;
    }


    #include "include/frontBackTopBottomPatches"
}


// ************************************************************************* //

frontBackTopBottomPatches

Code:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/


top
{
    type empty;
}

bottom
{
    type empty;
}

// ************************************************************************* //

initialConditions:

Code:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/

flowVelocity		(14.96346075389735890650 1.04634710616194826405 0);
pressure            0;
turbulentKE         0.03375;
turbulentOmega      0.12166;
reTheta				584.3046;
gammaInt			1; 
// ************************************************************************* //

controlDict:

Code:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#include        "../0/include/initialConditions"

application     simpleFoam;

startFrom       latestTime;

startTime       0;

stopAt          endTime;

endTime         20001;

deltaT          1;

writeControl    runTime;

writeInterval   5000;

purgeWrite      0;

writeFormat     binary;

writePrecision  6;

writeCompression off;

timeFormat      general;

timePrecision   6;

runTimeModifiable true;

functions
{
	probes
	{
		functionObjectLibs ( "libsampling.so" );
		type probes;
		name probes;
		fields
		(
			U
			p
		);

		probeLocations
		(
			(-2 	0 		0) // front
			(0  	-1 	0) // right
			(0		1	0) // left
			(2	0		0) // back
		);
	}
    forceMagnitudes
    {
        type                forces;
        libs                ("libforces.so");
        writeControl        timeStep;
        writeInterval       1;
        patches             (profile);
        rho                 rhoInf;
        log                 true;
        rhoInf              1;
        CofR                (0 0 0);
    }
	forceCoefficients
    {
        type                forceCoeffs;
        libs                ("libforces.so");
        outputControl       timeStep;
        outputInterval       1;
        patches             (profile);
		pName				p;
		UName				U;
        rho                 rhoInf;
        log                 true;
        rhoInf              1;
        CofR                (0 0 0);
		liftDir				(0 1 0);
		dragDir				(1 0 0);
		pitchAxis			(0 0 1);
		magUInf				15;
		lRef				1;
		Aref				1;
    }
	yPlus
    {
        type            yPlus;
        libs            ("libfieldFunctionObjects.so");
        writeControl    writeTime;
    }
	
	pressure1
	{
		type            pressure;
		libs            ("libfieldFunctionObjects.so");
		calcTotal       yes; // yes | no
		calcCoeff       yes; // yes | no
		writeControl    writeTime;


		// Optional entries

		// Field names
		p               p;
		U               U;
		rho             rho;

		// Total pressure: freestream pressure
		pRef            $pressure;
		pInf            100000;

		// Total pressure: freestream velocity magnitude
		UInf            $flowVelocity;

		// Total pressure: freestream density
		rhoInf          1.2;
	}
	
	surfaces
	{
		type            surfaces;
		libs            ("libsampling.so");
		writeControl    writeTime;

		surfaceFormat   vtk;
		fields          (p U);

		interpolationScheme cellPoint;

		surfaces
		(
			//zNormal
			//{
			//	type            cuttingPlane;
			//	planeType       pointAndNormal;
			//	pointAndNormalDict
			//	{
			//		point   (0 0 0.05);
			//		normal  (0 0 1);
			//	}
			//	interpolate     true;
			//}

			profile
			{
				type            patch;
				patches         (profile);
				interpolate     true;
			}
		);
	}
	
	
	
	wallShearStress1
	{
		type        	wallShearStress;
		libs        	("libfieldFunctionObjects.so");
		writeControl    writeTime;
		patches     	(profile);
	}

}


// ************************************************************************* //

fvScheme

Code:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
    default steadyState;
}

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

divSchemes
{
    default         				none;
    div(phi,U)                      bounded Gauss linearUpwind grad(U);
    div(phi,k)                      bounded Gauss linear;
    div(phi,omega)                  bounded Gauss linear;
	div(phi,gammaInt)   			bounded Gauss linearUpwind grad;
    div(phi,ReThetat)   			bounded Gauss linearUpwind grad;
	
    div((nuEff*dev2(T(grad(U)))))   Gauss linear;
}

laplacianSchemes
{
    default         Gauss linear corrected 0.33;
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    default         limited corrected 0.33;
}

wallDist
{
    method meshWave;
}


// ************************************************************************* //

fvSolution

Code:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solvers
{
    p
    {
        solver          GAMG;
        tolerance       1e-10;	//1e-5;
        relTol          0.1;
        smoother        GaussSeidel;
		maxIter 		500;	//4;
        minIter 		1;
    }
	
	Phi
	{
		$p;
	}
	
    U
    {
        solver           smoothSolver;
        smoother         GaussSeidel;
        tolerance        1e-5;
        relTol           0.1;
        nSweeps          1;
		maxIter 4;
        minIter 1;
    }

    k
    {
        solver           smoothSolver;
        smoother         GaussSeidel;
        tolerance        1e-5;
        relTol           0.1;
        nSweeps          1;
		maxIter 3;
        minIter 1;
    }

    omega
    {
        solver           smoothSolver;
        smoother         GaussSeidel;
        tolerance        1e-5;
        relTol           0.1;
        nSweeps          1;
		maxIter 3;
        minIter 1;
    }
	
	"(gammaInt|ReThetat)"
    {
        solver          smoothSolver;
        smoother        symGaussSeidel;
        tolerance       1e-8;
        relTol          0.1;
        maxIter         10;
    }
}

SIMPLE
{
   nNonOrthogonalCorrectors 1;
   residualControl
   {
		p               	5e-4;
        U               	1e-5;
        "(k|epsilon|omega|gammaInt|ReThetat)" 1e-5;
   }
}

potentialFlow
{
    nNonOrthogonalCorrectors 0;
}

relaxationFactors
{
    fields
    {
        p               0.8;
    }
    equations
    {
        "(U|k|omega)"   0.6;
        "(U|k|omega)Final" 1.0;
    }
}

cache
{
    grad(U);
}

// ************************************************************************* //

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
static vs. total pressure	auf dem feld	FLUENT	17	February 26, 2016 14:04
Airfoil pressure distribution	kanishkpanchal	Main CFD Forum	2	December 7, 2009 14:21
Neumann pressure BC and velocity field	Antech	Main CFD Forum	0	April 25, 2006 03:15
Gas pressure question	Dan Moskal	Main CFD Forum	0	October 24, 2002 23:02
Hydrostatic pressure in 2-phase flow modeling (CFX4.2)	HB &DS	CFX	0	January 9, 2000 14:19