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 rystokes October 7, 2010 07:33

planar vorticity calculation

Hi all,

I'm working on a secondary flow induced mixing in a T-shape channel. I'm interested in calculating the cross sectional or transversal directional planar vorticity which I believe can lead to the secondary flow pattern. However, the channel is not straight, zigzag shape instead. The difficulty is how to obtain the planar vorticity value on a certain cross sectional plane which is not parallel to any axis, i.e, x, y or z direction. I can't find any solution in CFX POST so far. Could anyone share me some advice plz? thanks.

Harry

 michael_owen October 7, 2010 14:38

Quote:
 Originally Posted by rystokes (Post 278257) Hi all, I'm working on a secondary flow induced mixing in a T-shape channel. I'm interested in calculating the cross sectional or transversal directional planar vorticity which I believe can lead to the secondary flow pattern. However, the channel is not straight, zigzag shape instead. The difficulty is how to obtain the planar vorticity value on a certain cross sectional plane which is not parallel to any axis, i.e, x, y or z direction. I can't find any solution in CFX POST so far. Could anyone share me some advice plz? thanks. Harry
Just do the math. Transform to find the vorticity component normal to the plane, square its magnitude, subtract that from the square of the full vorticity magnitude (which is independent of coordinate system), and take the square root.

 rystokes October 8, 2010 03:36

Hi,

I used function calculator in POST to obtain the value. Do you know how to get the normal component of vorticity？I established a vector normal to the plane, but I still don't know how to make use of this vector to get the normal component. Thanks.

 michael_owen October 12, 2010 15:34

Quote:
 Originally Posted by rystokes (Post 278392) Hi, I used function calculator in POST to obtain the value. Do you know how to get the normal component of vorticity？I established a vector normal to the plane, but I still don't know how to make use of this vector to get the normal component. Thanks.
Again, just do the math. Just project the vector vorticity onto the plane normal, i.e. calculate the dot product of the vorticity vector and the plane normal.

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