Calculate Skin Friction Coefficient in a plate with a roughness pattern
 

Hi everyone!

I'm having a problem to calculate a skin friction coefficient in a plate with a roughness pattern.
so, in a flat plate, the SFC is constant through the width axis but once my plate have small triangles the XY plot of ansys return me something like that:
(this mesh is really poor but is only to illustrate my problem)

https://fbcdn-sphotos-e-a.akamaihd.n...23146684_n.jpg

here you can see that SFC changes across the triangle

My question is: how can I calculate the average skin friction coefficient? Ansys or tecplot can do that?

thanks a lot