[salomama]

Hello Foamers;

I have had recently a tough time trying to implement and visualize the flow of a open test section in a closed return wind tunnel.
I solved all the problems related to creating the mesh and so on, and since i started using openfoam just lately i still need help.
This time, the results that i get, don't make any sense. I expect seeing a small shear layer outside the test section and a smooth flow inside the diffuser, due to the slot and the diffuser collector at the entry. What i get is reverse flow coming from the outlet, and very low velocity in the diffuser that goes to zero, and a loooot of turbulence that goes outside very far from the test section.

So my mesh is top view of the test section, It is cut into halfs, because i am considering the other half symmetrical. It has an inlet, which is in my case the end of the nozzle, test section that is 5 feet long and diffuser collector at the start of the diffuser, that is inclining by 7degrees. The diffuser has a slot of 2 inch wide and 1 inch long .
The design is 2D since there is no change z direction, and also for time consideration.
I chose icoFoam solver for laminar incompressible flow.
The slot is infinte in Z direction, which is not in reality (it is very small) but i doubt that this is the problem.
I am working with openfoam4 and visualizing my results with paraView.

The pictures of my results are attached.

Any help to recognize the source of the problem will be so much appreciated, i spent on this so much time.


FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField uniform 0;

boundaryField
{
inlet
{
type fixedFluxPressure;
value uniform 0;
gradient uniform 0;
}
outlet
{
type totalPressure;
p0 uniform 0;
value uniform 0;
}
leftside
{
type zeroGradient;
}
righttside
{
type zeroGradient;
}
symmetry
{
type symmetryPlane;
}
right1
{
type cyclic;
}
left1
{
type cyclic;
}
down1
{
type cyclic;
}
down2
{
type cyclic;
}
slot1
{
type cyclic;
}
slot2
{
type cyclic;
}
left3
{
type cyclic;
}
right3
{
type cyclic;
}
walls
{
type zeroGradient;
}
farfield
{
type zeroGradient;
}
frontAndBack
{
type empty;
}
}

//



FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solvers
{
p
{
solver PCG;
preconditioner DIC;
tolerance 1e-06;
relTol 0.05;
}

pFinal
{
$p;
relTol 0;
}

U
{
solver smoothSolver;
smoother symGaussSeidel;
tolerance 1e-05;
relTol 0;
}
}

PISO
{
nCorrectors 2;
nNonOrthogonalCorrectors 0;
pRefCell 0;
pRefValue 0;
}


FoamFile
{
version 2.0;
format ascii;
class volVectorField;
object U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField uniform (0 0 0);

boundaryField
{
inlet
{
type fixedValue;
value uniform (25 0 0);
}
outlet
{
type inletOutlet;
inletValue uniform (25 0 0);
value uniform (25 0 0);
}
leftside
{
type fixedValue;
value uniform (0 0 0);
}
righttside
{
type fixedValue;
value uniform (0 0 0);
}
symmetry
{
type symmetryPlane;
}
right1
{
type cyclic;
}
left1
{
type cyclic;
}
down1
{
type cyclic;
}
down2
{
type cyclic;
}
left3
{
type cyclic;
}
right3
{
type cyclic;
}
slot1
{
type cyclic;
}
slot2
{
type cyclic;
}
walls
{
type fixedValue;
value uniform (0 0 0);

}
farfield
{
type inletOutlet;
inletValue uniform (0 0 0);
value uniform (0 0 0);

}
frontAndBack
{
type empty;
}
}


FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "constant";
object transportProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

Transport Newtonian
nu [0 2 -1 0 0 0 0] 15.34e-6;


FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
default Euler;
}

gradSchemes
{
default Gauss linear;
grad(p) Gauss linear;
}

divSchemes
{
default none;
div(phi,U) Gauss linear;
}

laplacianSchemes
{
default Gauss linear orthogonal;
}

interpolationSchemes
{
default linear;
}

snGradSchemes
{
default orthogonal;
}


FoamFile
{
version 2.0;
format ascii;
class dictionary;
object blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

convertToMeters 1;

vertices
(
(0 -0.5 0) //0
(1.19 -0.5 0)
(0 0.5 0) //2
(1.19 0.5 0) //3
(0 0.91 0)
(1.49 0.91 0) //5
(0 -0.5 0.1)
(1.19 -0.5 0.1)
(0 0.5 0.1)
(1.19 0.5 0.1) //9
(0 0.91 0.1)
(1.49 0.91 0.1) //11
(0 0.91 0)
(1.49 0.91 0) //13
(0 1.21 0)
(1.49 1.21 0) //15
(0 0.91 0.1)
(1.49 0.91 0.1) //17
(0 1.21 0.1) //
(1.49 1.21 0.1) //19

(1.19 -0.5 0) //20

(1.68 -0.5 0) //21
(1.73 -0.5 0) //22

(2.7 -0.5 0) // 23
(1.19 0.5 0) //24
(1.68 0.5 0) //
(1.73 0.5 0) //26
(2.7 0.5 0) //27
(1.49 0.91 0) //28
(1.68 0.88 0) //29
(1.73 0.87 0) //
(2.7 0.73 0) //31
(1.19 -0.5 0.1) //32

(1.68 -0.5 0.1) //33
(1.73 -0.5 0.1) //34

(2.7 -0.5 0.1) //35
(1.19 0.5 0.1) //36
(1.68 0.5 0.1) //
(1.73 0.5 0.1) //
(2.7 0.5 0.1) //39
(1.49 0.91 0.1) //40
(1.68 0.88 0.1) //
(1.73 0.87 0.1) //
(2.7 0.73 0.1) //43
(1.49 0.91 0) //44
(1.68 0.88 0) //
(1.73 0.87 0) //
(2.7 0.73 0) //47
(1.49 1.21 0) //48
(1.68 1.21 0) //
(1.73 1.21 0) //50
(2.7 1.21 0) //51
(1.49 0.91 0.1) //52
(1.68 0.88 0.1) //
(1.73 0.87 0.1) //54
(2.7 0.73 0.1) //55
(1.49 1.21 0.1) //56
(1.68 1.21 0.1) //57
(1.73 1.21 0.1) //58
(2.7 1.21 0.1) //59


);

blocks
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hex (0 1 3 2 6 7 9 8) (20 20 1) simpleGrading (1 1 1)
hex (2 3 5 4 8 9 11 10) (20 20 1) simpleGrading (1 1 1)
hex (12 13 15 14 16 17 19 18) (20 20 1) simpleGrading (1 1 1)

hex (20 21 25 24 32 33 37 36) (20 20 1) simpleGrading (1 1 1)
hex (21 22 26 25 33 34 38 37) (3 20 1) simpleGrading (1 1 1)
hex (22 23 27 26 34 35 39 38) (20 20 1) simpleGrading (1 1 1)


hex (24 25 29 28 36 37 41 40) (20 20 1) simpleGrading (1 1 1)
hex (25 26 30 29 37 38 42 41) (3 20 1) simpleGrading (1 1 1)
hex (26 27 31 30 38 39 43 42) (20 20 1) simpleGrading (1 1 1)

hex (44 45 49 48 52 53 57 56) (10 20 1) simpleGrading (1 1 1)
hex (45 46 50 49 53 54 58 57) (3 20 1) simpleGrading (1 1 1)
hex (46 47 51 50 54 55 59 58) (20 20 1) simpleGrading (1 1 1)
);


edges
(
);

boundary
(
inlet
{
type patch;
faces
(
(12 16 18 14)
);
}
outlet
{
type patch;
faces
(
(47 51 59 55)
);
}
leftside
{
type patch;
faces
(
(2 8 10 4)
(0 6 8 2)
);
}
righttside
{
type patch;
faces
(
(27 31 43 39)
(23 27 39 35)
);
}
symmetry
{
type symmetryPlane;
faces
(
(14 18 19 15)
(48 56 57 49)
(49 57 58 50)
(50 58 59 51)
);
}

right1
{
type cyclic;
neighbourPatch left1;
faces
(
(44 52 56 48)
);
}
left1
{
type cyclic;
neighbourPatch right1;
faces
(
(13 15 19 17)
);
}



down1
{
type cyclic;
neighbourPatch down2;
faces
(
(12 13 17 16)
);
}
down2
{
type cyclic;
neighbourPatch down1;
faces
(
(4 10 11 5)
);
}



slot1
{
type cyclic;
neighbourPatch slot2;
faces
(
(45 46 54 53)
);
}
slot2
{
type cyclic;
neighbourPatch slot1;
faces
(
(29 41 42 30)
);
}
left3
{
type cyclic;
neighbourPatch right3;
faces
(
(1 3 9 7)
);
}
right3
{
type cyclic;
neighbourPatch left3;
faces
(
(20 32 36 24)
);
}
walls
{
type wall;
faces
(
(24 36 40 28)
(28 40 41 29)
(30 42 43 31)
(44 45 53 52)
(46 47 55 54)
(3 5 11 9)
);
}
farfield
{
type patch;
faces
(
(0 1 7 6)
(20 21 33 32)
(21 22 34 33)
(22 23 35 34)
);

}
frontAndBack
{
type empty;
faces
(
(0 2 3 1)
(2 4 5 3)
(6 7 9 8)
(8 9 11 10)

(12 14 15 13)
(16 17 19 18)

(20 24 25 21)
(21 25 26 22)
(22 26 27 23)
(24 28 29 25)
(25 29 30 26)
(26 30 31 27)

(32 33 37 36)
(33 34 38 37)
(34 35 39 38)
(36 37 41 40)
(37 38 42 41)
(38 39 43 42)

(44 48 49 45)
(45 49 50 46)
(46 50 51 47)
(52 53 57 56)
(53 54 58 57)
(54 55 59 58)
);
}

);

mergePatchPairs
(
);