[TML]

Hello,

I am running a 2D annular flow case, and I am trying to get velocity distribution at a certain location using sample utility. The problem is that the result gives by sample does not include the boundary point which should be (0 0 0) for a no-slip wall. I have tried cellPoint, cellPointFace, and cellPatchConstrained for the interpolationScheme, but none of them works.

This is my sampleDict:

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

setFormat csv;


interpolationScheme cellPatchConstrained;


fields
(
Ux
);

sets
(
lineX1
{
type uniform;
axis y;

start (0.06 0.02 0); //inner wall
end (0.06 0.03 0); //outer wall
nPoints 40;
}

);
//************************************************** * //

Any help is appreciated!

[piu58]

You let sample calculate the values at a very short perpendicular line which doesn't contain your (0 0 0 ) point.

[TML]

Originally Posted by piu58

You let sample calculate the values at a very short perpendicular line which doesn't contain your (0 0 0 ) point.

Thanks for the reply.

But my start and end point are on the inner and outer wall of the annular cylinder respectively, which should contain the (0 0 0) velocity.

[piu58]

Please keep in mind: The velocity is modeled, and the last calculated value is the one of the first cell beyond the boundary. Values inside this cell (toward the boundary) are extrapolated.
Beside this it depends form your wall function which velocity you get near the boundary. There is a contradiction between capturing the behavior of the flow very near the boundary and the overall approach of the boundary layer: Both can only covered with DNS.

It may be en-lighting of you look at the velocity at every cell around the cylinder and next the cell toward the flow.