[mohammad]

Hi everybody.
I have solved a 3D blade. I want to extract the location of separation point from the results.

Which parameter best shows the Separation Point ? I remember it was one of stress component but i don't remember it clearly.

Regards,

[truffaldino]

Originally Posted by mohammad

Hi everybody.
I have solved a 3D blade. I want to extract the location of separation point from the results.

Which parameter best shows the Separation Point ? I remember it was one of stress component but i don't remember it clearly.

Regards,

This is a point where tangential (shear stress) force vanishes. This is the point where dv_t/dn=0, where v_t is tangential velocity and n is coordinate normal to the surface

[mohammad]

Originally Posted by truffaldino

This is a point where tangential (shear stress) force vanishes.

Hi truffaldino,
I know that it must be shear stress...and in CFD we have the "shear-wall- stress" for that. My question is that which of the "sheat-wall- stresses"( X,y,z) or the resultant ??

[truffaldino]

For flows which are not quasi 2D: the 3D boundary layer flow the point of separation is not necessarily a point of zero surface stress

For more details see this forum

http://www.cfd-online.com/Forums/mai...w-problem.html

If your flow is quasi 2D, then the separation/reattachment lines will be approximately at the minimum of absolute value of the shear stress