[jimbean]

Hi,

I am trying to set up a case, like cavity, in icoFoam folder.

The case is to simulate 3D water flow around two tandem cylinders in open channel.

The mesh is generated with Gridgen (see attached figure, top view), hexahedral.

The left is inlet boundary and right is outlet boundary. The surface give symmetry boundary and the side and bottom wall are wall boundary.

velocity-inlet-4
{
type patch;
nFaces 56;
startFace 16992;
}
wall-5
{
type wall;
nFaces 4120;
startFace 17048;
}
symmetry-6
{
type symmetryPlane;
inGroups 1(symmetryPlane);
nFaces 3528;
startFace 21168;
}
outflow-8
{
type patch;
nFaces 56;
startFace 24696;
}


Initial boundary: P
dimensions [0 2 -2 0 0 0 0];

internalField uniform 0;

boundaryField
{
velocity-inlet-4
{
type zeroGradient;
}

wall-5
{
type zeroGradient;
}
outflow-8
{
type fixedValue;
value uniform 0;
}
symmetry-6
{
type symmetryPlane;
}
}

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

internalField uniform (0 0 0);

boundaryField
{
velocity-inlet-4
{
type fixedValue;
value uniform (0.1 0 0);
}
outflow-8
{
type zeroGradient;
}
symmetry-6
{
type symmetryPlane;
}
wall-5
{
type fixedValue;
value uniform (0 0 0);
}

}

I also changed the deltaT to make sure the Courant number is less than 1.
For the fvschemes and fvsolution i didn't change them.

With these modifies, i run the checkMesh. The mesh is ok.
And the icoFoma,
The Courant number increases too high and make the calculation break down.

Could anyone help me out?

Best