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How to determine the separation point on an airfoil???

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Old   May 1, 2012, 23:39
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mohammad
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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,
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Old   May 2, 2012, 04:39
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Quote:
Originally Posted by mohammad View Post
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
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Old   May 2, 2012, 04:47
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Originally Posted by truffaldino View Post
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 ??
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Old   May 2, 2012, 05:27
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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

how to evaluate seperation in 3D flow problem?

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