Hi

I am trying to get info regarding shear stress within a rectangular channel. I designed the channel, set boundary conditions and now I want shear stress from the flow simulation.

1) I used a surface plot to get shear stress but I am getting confused since it says shear stress or shear stress(x) --> What does it refer with shear stress(x)?

2) I set it to give me the shear stress on all faces - but I am confused as what the surface plot is showing me - is it the shear stress on the wall (meaning top wall)? or is it the shear stress on all faces averaged? What does the option 'use all faces' mean?

3) Also - Ive been trying to get shear rate within the channel, so Ive drawn a line using xy-plot extracted the data and gotten the derivative of velocity with respect to vertical distance to get the shear rate, but since the steps between points are to large the values I get I think are too high and it does not agree with the shear stress values I obtain ( I do shear rate*viscosity)

So - how can i get the values of shear stress? On the top and bottom of the channel?

and how can i get shear rate? Is the xy-plot approach the only way?

Thanks in advance!

Maria