I see that though the walls are defined as noSlip, when I plot a graph I get a non-zero value of the velocity at walls. How is this possible? Should I be refining the mesh? In paraview also I was able to see a non-zero value in the contours. And this non-zero value is not so insignificant to be ignored.
I tried to fix this issue by referring to other forums, where they mentioned it was an issue of paraFoam which was't interpolating the cell center values well, where the software is presuming zero gradient instead of noSlip at boundaries. They suggested to use foamToVTK and then open the file in ParaView. Though I followed it and it fixed the contours, but when graphed there is no change in results. I still get a non-zero velocity at the walls.
How to fix this issue and why is this appearing?