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MRF SimpleFoam - Wind Turbine Blade - Underestimating forces

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Old   October 28, 2021, 12:00
Post MRF SimpleFoam - Wind Turbine Blade - Underestimating forces
  #1
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Join Date: Sep 2021
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Hello,

I am trying to simulate in a steady flow a 15 MW IEA turbine blade in a 120 axisymmetric wedge domain.
The size of the domain is 2 radii in front of the blade, 5 radii behind and 1.5 radii high.
There are 2 regions in the mesh: Rotor that moves at -0.76 rad/s, and external wedge (cunha_externa) that is stationary.
The moment at x, converged at -1.72E+6Nm. Whereas by the technical parameters approx. -5.7E+6Nm is expected (power coefficient (cp) = 0.489).
I don't know what I am doing wrong, with the dynamic mesh method and transient solver I achieved the results.
I'm using the simplefoam solver with mrf.
The turbulence model is K Omega SST.
Definition of iea 15mw: https://www.nrel.gov/docs/fy20osti/75698.pdf
Mesh and results: https://drive.google.com/drive/folde...bC?usp=sharing
I tried to simulate a in a similar way of the case iv from this article (https://doi.org/10.1016/j.renene.2018.07.062)
Boundaries:
U
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2106                                  |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      binary;
    arch        "LSB;label=32;scalar=64";
    class       volVectorField;
    location    "0";
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField   uniform (-10 0 0);

boundaryField
{
    pa
    {
        type            noSlip;
    }
    "(lateral|entrada)"
    {
        type            fixedValue;
        value           $internalField;
    }
    saida
    {
        type            zeroGradient;
    }
    "(lado0|lado120)"
    {
        type            cyclicAMI;
    }
	"(AMI_1|AMI_2)"
    {
        type            cyclicAMI;
    }
}

// ************************************************************************* //
p
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2106                                  |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      binary;
    arch        "LSB;label=32;scalar=64";
    class       volScalarField;
    location    "0";
    object      p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField   uniform 0;

boundaryField
{
    "(pa|lateral|entrada)"
    {
        type            zeroGradient;
    }
    saida
    {
        type            fixedValue;
        value           $internalField;
    }
    "(lado0|lado120)"
    {
        type            cyclicAMI;
    }
	"(AMI_1|AMI_2)"
    {
        type            cyclicAMI;
    }
}


// ************************************************************************* //
k
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2106                                  |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      binary;
    arch        "LSB;label=32;scalar=64";
    class       volScalarField;
    location    "0";
    object      k;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField   uniform 0.06;

boundaryField
{
    pa
    {
        type            kqRWallFunction;
        value           $internalField;
    }
    "(entrada|lateral)"
    {
        type            fixedValue;
        value           $internalField;
    }
    saida
    {
        type            zeroGradient;
    }
    "(lado0|lado120)"
    {
        type            cyclicAMI;
    }
	"(AMI_1|AMI_2)"
    {
        type            cyclicAMI;
    }
}


// ************************************************************************* //
omega
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2106                                  |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      binary;
    arch        "LSB;label=32;scalar=64";
    class       volScalarField;
    location    "0";
    object      omega;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField   uniform 4.5939;

boundaryField
{
    pa
    {
        type            omegaWallFunction;
        value           $internalField;
    }
    "(entrada|lateral)"
    {
        type            fixedValue;
        value           $internalField;
    }
    saida
    {
        type            zeroGradient;
    }
    "(lado0|lado120)"
    {
        type            cyclicAMI;
    }
	"(AMI_1|AMI_2)"
    {
        type            cyclicAMI;
    }
}


// ************************************************************************* //
nut
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2106                                  |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      binary;
    arch        "LSB;label=32;scalar=64";
    class       volScalarField;
    location    "0";
    object      nut;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField   uniform 0;

boundaryField
{
    pa
    {
        type            nutkWallFunction;
        value           $internalField;
    }
    "(entrada|saida|lateral)"
    {
        type            calculated;
        value           $internalField;
    }
    "(lado0|lado120)"
    {
        type            cyclicAMI;
    }
	"(AMI_1|AMI_2)"
    {
        type            cyclicAMI;
    }
}


// ************************************************************************* //
MRFProperties
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2106                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      MRFProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

MRF1
{
    cellZone    Rotor_zone;
    active      yes;

    // Fixed patches (by default they 'move' with the MRF zone)
    nonRotatingPatches (AMI_1 AMI_2);
	origin      (0 0 0);
	axis        (1 0 0);
	omega       0.769230769231; // rad/s
}


// ************************************************************************* //
fvSchemes
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  5                                     |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
	default         steadyState;
}

gradSchemes
{
	default	Gauss linear;
}


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

laplacianSchemes
{
	default	Gauss linear corrected;
}

snGradSchemes
{
	default	corrected;
}

wallDist
{
	method	meshWave;
}


// ************************************************************************* //
fvSolution
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  5                                     |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solvers
{
    p
    {
        solver          GAMG;
        tolerance       1e-7;
        relTol          0;
        smoother        GaussSeidel;
		cacheAgglomeration no;
		maxIter	500;
    }

    "(U|k|omega)"
    {
        solver          smoothSolver;
        smoother        GaussSeidel;
        tolerance       1e-7;
        relTol          0;
        nSweeps         2;
    }
}
SIMPLE
{
    nNonOrthogonalCorrectors 0;
    consistent      yes;
	pRefCell	0;
	pRefValue	0;
	residualControl
	{
	p	1e-6;
	"(U|k|omega)"	1e-6;
	}
}

relaxationFactors
{
    fields
    {
        p               0.3;
    }
    equations
    {
        "(U|k|omega)"   0.7;
    }
}


// ************************************************************************* //
forcesImcompressible
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  5                                     |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      forcesIncompressible;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

forces
{
	functionObjectLibs 	("libforces.so");
	
    patches     		(pa);
    CofR        		(3.770655 0 0);
    pitchAxis   		(0 0 0);
	writeControl		adjustableRunTime;
	writeInterval		1;
	type            	forces;
	pName           	p;
	UName           	U;
	rho         		rhoInf; // Incompressible solver
	rhoInf      		1.18732;
	log             	true;
}

// ************************************************************************* //
checkMesh
Code:
/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2106                                  |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : _7b82832f-20210625 OPENFOAM=2106
Arch   : "LSB;label=32;scalar=64"
Exec   : checkMesh
Date   : Oct 28 2021
Time   : 12:36:07
Host   : DESKTOP-H7B8IOF
PID    : 510
I/O    : uncollated
Case   : iea_15mw
nProcs : 1
trapFpe: Floating point exception trapping enabled (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 5, maxFileModificationPolls 20)
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0

Time = 0

Mesh stats
    points:           15087385
    faces:            43973155
    internal faces:   43441104
    cells:            14447935
    faces per cell:   6.050294
    boundary patches: 8
    point zones:      0
    face zones:       0
    cell zones:       2

Overall number of cells of each type:
    hexahedra:     13867146
    prisms:        153181
    wedges:        0
    pyramids:      0
    tet wedges:    129
    tetrahedra:    0
    polyhedra:     427479
    Breakdown of polyhedra by number of faces:
        faces   number of cells
            4   8873
            5   7662
            6   65466
            7   150255
            8   20204
            9   117862
           10   552
           11   119
           12   50013
           13   2
           14   19
           15   6408
           18   44

Checking topology...
    Boundary definition OK.
    Cell to face addressing OK.
    Point usage OK.
    Upper triangular ordering OK.
    Face vertices OK.
   *Number of regions: 2
    The mesh has multiple regions which are not connected by any face.
  <<Writing region information to "0/cellToRegion"
  <<Writing region 0 with 4975517 cells to cellSet region0
  <<Writing region 1 with 9472418 cells to cellSet region1

Checking patch topology for multiply connected surfaces...
                   Patch    Faces   Points                  Surface topology
                 entrada     8482     8557  ok (non-closed singly connected)
                   saida     8482     8557  ok (non-closed singly connected)
                   lado0    46631    48006  ok (non-closed singly connected)
                 lado120    46736    48116  ok (non-closed singly connected)
                 lateral    68880    69465  ok (non-closed singly connected)
                      pa   274482   283476  ok (non-closed singly connected)
                   AMI_2    39182    39181  ok (non-closed singly connected)
                   AMI_1    39176    39405  ok (non-closed singly connected)

Checking faceZone topology for multiply connected surfaces...
    No faceZones found.

Checking basic cellZone addressing...
                CellZone        Cells       Points       VolumeBoundingBox
          cunha_externa      4975517      5070077 2.821492e+07 (-600 -155.8846 -3.64628e-16) (240 155.8846 180)
             Rotor_zone      9472418     10017308     282470.2 (-4.006414 -112.5832 -1.408003e-05) (12.00412 112.5835 130)

Checking geometry...
    Overall domain bounding box (-600 -155.8846 -1.408003e-05) (240 155.8846 180)
    Mesh has 3 geometric (non-empty/wedge) directions (1 1 1)
    Mesh has 3 solution (non-empty) directions (1 1 1)
    Boundary openness (2.330773e-17 7.088203e-16 5.225327e-14) OK.
    Max cell openness = 3.308378e-15 OK.
    Max aspect ratio = 66.99643 OK.
    Minimum face area = 3.874454e-06. Maximum face area = 8.968646.  Face area magnitudes OK.
    Min volume = 1.148255e-06. Max volume = 11.81478.  Total volume = 2.849739e+07.  Cell volumes OK.
    Mesh non-orthogonality Max: 63.7486 average: 4.455527
    Non-orthogonality check OK.
    Face pyramids OK.
    Max skewness = 3.998489 OK.
    Coupled point location match (average 0) OK.

Mesh OK.

End
Thank you for the advice,
Attached Images
File Type: jpg mesh1.jpg (19.2 KB, 28 views)
File Type: jpg U_90.jpg (29.3 KB, 23 views)
File Type: jpg U_90_close.jpg (23.3 KB, 16 views)
File Type: jpg U_90x.jpg (21.8 KB, 13 views)
File Type: jpg U_90y.jpg (22.5 KB, 13 views)
hgropelli is offline   Reply With Quote

Old   March 16, 2022, 06:32
Default
  #2
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hgropelli is on a distinguished road
Solution:
Increase the MRF domain (non inertial) to 2 blade diameters of lenght and 2 blade diameters of height with the blade in the middle
Attached Images
File Type: jpg q001velocitycontour_yplane-min.jpg (42.0 KB, 21 views)
File Type: jpg p07-min.jpg (23.8 KB, 16 views)
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