Keyur Kanade
Ansys Employee

Make sure you have that face in geometry. If you do not have that face in geometry, go to SpaceClaim and split the faces so that you have that face. 

In SpaceClaim you can create NS using Groups. 

In Meshing , select that face, right click and create NS. 

Please go through help manual for more details 

Regards,

Keyur

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