[Naruto]

Hello,
I am currently using OpenFOAM for 3-D simulation of Vertical Axis Wind Turbine. Actually I moved on to 3-D simulation after 2-D simulation. My current problem is I am getting too large negative Cp. Infact sometimes it may go beyond 1. Here is the result of my CheckMesh utility:
/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.2.2 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 2.2.2-9739c53ec43f
Exec : checkMesh
Date : Jan 06 2014
Time : 23:47:53
Host : "hpcmaster01"
PID : 17376
Case : /home/Turbine_BUET_0_exp.
nProcs : 1
sigFpe : Floating point exception trapping - not supported on this platform
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Disallowing user-supplied system call operations

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

Create polyMesh for time = 0

Time = 0

Mesh stats
points: 1001176
faces: 6019344
internal faces: 5930454
cells: 2665263
faces per cell: 4.48353
boundary patches: 10
point zones: 0
face zones: 0
cell zones: 2

Overall number of cells of each type:
hexahedra: 603260
prisms: 0
wedges: 0
pyramids: 82226
tet wedges: 0
tetrahedra: 1979777
polyhedra: 0

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"

Checking patch topology for multiply connected surfaces...
Patch Faces Points Surface topology
blade-2 31703 30935 ok (closed singly connected)
Rotor 5144 2692 ok (non-closed singly connected)
blade-1 31703 30935 ok (closed singly connected)
Rotor-AMI 5782 5900 ok (non-closed singly connected)
topAndBottom 2678 1447 ok (non-closed singly connected)
Stator 5144 2692 ok (non-closed singly connected)
inlet 171 200 ok (non-closed singly connected)
sides 612 700 ok (non-closed singly connected)
outlet 171 200 ok (non-closed singly connected)
Stator-AMI 5782 5900 ok (non-closed singly connected)

Checking geometry...
Overall domain bounding box (-15 -10 -2.5) (25 10 3)
Mesh (non-empty, non-wedge) directions (1 1 1)
Mesh (non-empty) directions (1 1 1)
Boundary openness (1.48176e-18 7.67635e-17 -1.5866e-18) OK.
Max cell openness = 3.39725e-16 OK.
Max aspect ratio = 61.3245 OK.
Minimum face area = 2.18162e-08. Maximum face area = 1.57259. Face area magnitudes OK.
Min volume = 1.75721e-12. Max volume = 0.535229. Total volume = 4400. Cell volumes OK.
Mesh non-orthogonality Max: 70.075 average: 19.2599
*Number of severely non-orthogonal (> 70 degrees) faces: 2.
Non-orthogonality check OK.
<<Writing 2 non-orthogonal faces to set nonOrthoFaces
Face pyramids OK.
Max skewness = 1.66154 OK.
Coupled point location match (average 0) OK.

Mesh OK.

End

As you may see from the checkMesh utility the mesh is fine. But there is only one thing that may be a reason for abnormality and that is:
"The mesh has multiple regions which are not connected by any face."

What does it mean? I got the same message while 2-D simulation too. But in case of 2-D I got good results. I have modelled my whole problem after the propeller tutorial. In my opinion the problem may arise from the fvSchemes or fvSolutions too. I am posting it here.

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

ddtSchemes
{
default Euler;
}

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

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

laplacianSchemes
{
default Gauss linear corrected;
}

interpolationSchemes
{
default linear;
}

snGradSchemes
{
default corrected;
}

fluxRequired
{
default no;
pcorr ;
p ;
}


//
solvers
{
pcorr
{
solver GAMG;
tolerance 1e-7;
relTol 0.005;
smoother GaussSeidel;
nPreSweeps 0;
nPostSweeps 2;
cacheAgglomeration off;
agglomerator faceAreaPair;
nCellsInCoarsestLevel 20;
mergeLevels 1;
maxIter 100;
minIter 1;
}
p
{
$pcorr;
tolerance 1e-5;
relTol 0.01;
}

pFinal
{
$p;
tolerance 1e-6;
relTol 0;
}

"(U|k|epsilon|omega|nuTilda)"
{
solver smoothSolver;
smoother GaussSeidel;
nSweeps 1;
tolerance 1e-07;
relTol 0.05;
maxIter 100;
minIter 1;
};
"(U|k|epsilon|omega|nuTilda)Final"
{
solver smoothSolver;
smoother GaussSeidel;
nSweeps 2;
tolerance 1e-07;
relTol 0.05;
maxIter 100;
minIter 1;
}
}

PISO
{
nCorrectors 2; // PISO loop
// not used in turbSimpleDyMFoam
nOuterCorrectors 2; // PIMPLE loop
nNonOrthogonalCorrectors 0;
correctPhi true;
}

PIMPLE
{
nOuterCorrectors 2;
nCorrectors 2;
nNonOrthogonalCorrectors 0;
correctPhi true;

}

SIMPLE
{
nNonOrthogonalCorrectors 0;
pRefCell 0;
pRefValue 0;
}

relaxationFactors
{

p 0.3;
U 0.7;
k 0.6;
omega 0.6;
epsilon 0.6;

}


I am at lost at the moment. I would really appreciate any help from you.