Solving Parallel Plate Flow with icoFoam
 

Good day all,


I am trying to run a simple parallel plate flow case using the icoFoam solver. However, I am getting a strange result for my velocity field, shown in the image below. I have had a look at the icoFoam - Elbow tutorial, which I understand to have similar boundary conditions. I suspect I might be missing something really simple, but cannot figure out what is wrong. I have tried a few different combinations of boundary conditions. Any pointers would be greatly appreciated. My blockMeshDict, p and U files are included below.

https://www.cfd-online.com/Forums/da...AAAElFTkSuQmCC
My blockMeshDict file body:

scale 1;

vertices
(
(0.01 0.005 -0.1)
(-0.01 0.005 -0.1)
(-0.01 -0.005 -0.1)
(0.01 -0.005 -0.1)
(0.01 0.005 0.1)
(-0.01 0.005 0.1)
(-0.01 -0.005 0.1)
(0.01 -0.005 0.1)
);

blocks
(
hex (0 1 2 3 4 5 6 7) (4 1 40) simpleGrading (1 1 1)
);

edges
(
);

boundary
(
fixedWalls
{
type wall;
faces
(
(1 5 4 0)
(3 7 6 2)
);
}
frontback
{
type empty;
faces
(
(2 6 5 1)
(0 4 7 3)
);
}
inlet
{
type patch;
faces
(
(0 3 2 1)
);
}
outlet
{
type patch;
faces
(
(4 5 6 7)
);
}
);

My boundary conditions for p:

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

internalField uniform 0;

boundaryField
{
fixedWalls
{
type zeroGradient;
}

inlet
{
type zeroGradient;
}

outlet
{
type fixedValue;
value uniform 0;
}

frontback
{
type empty;
}
}


My boundary conditions for U:

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

internalField uniform (0 0 0);

boundaryField
{
fixedWalls
{
type noSlip;
}

inlet
{
type fixedValue;
value uniform (0 0 1);
}

outlet
{
type zeroGradient;
}

frontback
{
type empty;
}
}

Hello!,

4 cell in x direction is too few. Increase the number to, lets say, 10.

I suppose the y direction is the empty one. In this case one cell is sufficient.

The velocity in z direction should be -1 instead of 1, if the inlet at the top. Else it is right.

The velocity at the outlet should be changed to inletOutlet instead of zeroGradient.

Regards

Peter

Hi Peter,

Thank you for your reply. My inlet is at the bottom, thus I kept it at 1 m/s (+Z). Velocity at the outlet is now an inletOutlet boundary condition. I also realized that my fixedWalls (noSlip condition) and frontback (empty condition) was swapped around, i.e. only one cell between my noSlip walls. I made the changes and now it works, screenshot of velocity field attached.

Kind regards,
Johannes