[sona]

Hey all,

I'm trying to run a steady state simpleFoam case on a square channel (only quarter part) with symmetric planes. The mesh is generated in blockMeshDict.The model used is kEpsilon with wall function. The fluid used is water.The Reynolds no is 20000.The axial velocity profile in the radial direction is plotted in terms of y+ Vs U+(Axial velocity normalized with friction velocity) and compared with universal velocity profile. But the prediction in the buffer region (y+= 8-30) is not matching with universal velocity profile. Hope you can help me.

Thanks and Regards

Sona

Here I attached the blockMeshDict, U,p,k,epsilon fields, ControlDict,fvSolution and fvSchemes files used.

blockMeshDict

convertToMeters 1.0;

vertices
(
(0 0 0)
(0.005 0 0)
(0.005 0.005 0)
(0 0.005 0)
(0 0 0.5)
(0.005 0 0.5)
(0.005 0.005 0.5)
(0 0.005 0.5)

);



blocks
(
hex (0 1 2 3 4 5 6 7) (50 50 100) simpleGrading (1 1 1)

);

patches
(
patch inlet
(
(0 1 2 3)
)
patch outlet
(
(4 5 6 7)
)
wall walls
(
(1 5 6 2)
(2 6 7 3)
)
symmetryPlane sides
(
(0 1 5 4)
(0 3 7 4)
)

);

mergePatchPairs
(
);

U


internalField uniform (0 0 0);

boundaryField
{
inlet
{
type fixedValue;
value uniform (0 0 2);
}

outlet
{
type zeroGradient;
}

walls
{
type fixedValue;
value uniform (0 0 0);
}

sides
{
type symmetryPlane;
}
}

p file


internalField uniform 0;

boundaryField
{
inlet
{
type zeroGradient;
}

outlet
{
type fixedValue;
value uniform 0;
}

walls
{
type zeroGradient;
}

sides
{
type symmetryPlane;
}
}

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

internalField uniform 0.01286;

boundaryField
{
inlet
{
type fixedValue;
value uniform 0.01286;
}
outlet
{
type zeroGradient;
}
walls
{
type kqRWallFunction;
value uniform 0.01286;
}

sides
{
type symmetryPlane;
}
}

epsilon

dimensions [0 2 -3 0 0 0 0];

internalField uniform 0.3399;

boundaryField
{
inlet
{
type fixedValue;
value uniform 0.3399;
}
outlet
{
type zeroGradient;
}
walls
{
type epsilonWallFunction;
value uniform 0.3399;
}

sides
{
type symmetryPlane;
}
}

[sona]

Further Details:

fvSolution
solvers
{
p
{
solver GAMG;
tolerance 1e-08;
relTol 0;
smoother GaussSeidel;
nPreSweeps 0;
nPostSweeps 2;
cacheAgglomeration true;
nCellsInCoarsestLevel 100;
agglomerator faceAreaPair;
mergeLevels 1;

}

U
{
solver smoothSolver;
smoother GaussSeidel;
nSweeps 2;
tolerance 1e-08;
relTol 0;
}

k
{
solver smoothSolver;
smoother GaussSeidel;
nSweeps 2;
tolerance 1e-08;
relTol 0;
}

epsilon
{
solver smoothSolver;
smoother GaussSeidel;
nSweeps 2;
tolerance 1e-08;
relTol 0;
}

}

SIMPLE
{
nNonOrthogonalCorrectors 0;
convergence 1e-06;
}

relaxationFactors
{
p 0.3;
U 0.7;
k 0.7;
epsilon 0.7;

}

fvSchemes

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

[sona]

The graph (comparison of axial velocity with universal velocity profile)

[sona]

[sona]

Graph of universal velocity profile from simulation and from correlation is attached

[sdharmar]

Hi,
How did you get this yplus values
BR,
Suranga.