# NURBS surfaces on a wing

 Register Blogs Members List Search Today's Posts Mark Forums Read

January 24, 2017, 23:27
NURBS surfaces on a wing
#1
Member

Ferruccio Rossi
Join Date: Jun 2016
Location: Melbourne, FL USA
Posts: 91
Rep Power: 9
Hi all,

I am meshing an airplane wing inside an enclosure. Both pictures show only the wing surfaces inside the enclosure (the enclosure faces have been hidden). I am using two different modeling methods:

METHOD 1: import 3D curves of the airfoils and obtain the wing with few surfaces (pic 1)

METHOD 2: import coordinate points and obtain the wing out of many surfaces (pic 2)

As you can see from the pictures, METHOD 1 is clearly preferable to work with, but when I open the mesher it says "The following faces have high order NURBS surfaces. These may take longer to mesh"
And the mesh takes forever!
On the other hand, if I use method 2 the mesh takes a normal amount of time.

Any idea on how to solve the problem? I would prefer to work with METHOD 1 since there are only a few surfaces on the wing compared to the hundreds of surfaces of METHOD 2.

Attached Images
 4.jpg (30.1 KB, 90 views) 2.jpg (37.4 KB, 81 views)

 January 25, 2017, 06:22 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,480 Rep Power: 140 Try importing the solid geometry with a different solid model format. Parasolid is often the best one, but if that does not work try STEP, ACIS or IGES.

January 25, 2017, 17:09
#3
Member

Ferruccio Rossi
Join Date: Jun 2016
Location: Melbourne, FL USA
Posts: 91
Rep Power: 9
Ghorrocks,

Thank you for you answer. But I modeled the wing into Design Modeler. As you can see from the picture, the wing is inside a fluid domain but it has been removed using a Boolean operation. So what is left is just the hole left by the wing inside the fluid.

Following your suggestion, I exported my wing as a Parasolid file and then I imported it again as a Parasolid file and remade the enclosure around it, but it still generates NURBS when I open the mesher.
Any ideas? I am stuck since it takes forever even to generate the simplest mesh without any modification.

And which format is better between Parasolid text and Parasolid binary?

Best regards.
Attached Images
 1.png (46.1 KB, 40 views)

Last edited by frossi; January 25, 2017 at 19:22.

 January 26, 2017, 00:31 #4 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,480 Rep Power: 140 There is no difference between parasols text and binary files, other than the obvious. The solid model data is the same. If you are getting these problems with a design modern geometry than no import/export is required. It shows something is likely to be wacky in the way you drew the geometry. frossi likes this.

 January 26, 2017, 01:36 #5 Senior Member   urosgrivc Join Date: Dec 2015 Location: Slovenija Posts: 365 Rep Power: 10 What about geometry simplification... https://www.sharcnet.ca/Software/Ans...BodyOpSimplify I had same problems and it worked, just make sure it doesent change the geometry too much, it usualy doesent. frossi likes this.

 February 5, 2017, 15:27 #6 Member   Ferruccio Rossi Join Date: Jun 2016 Location: Melbourne, FL USA Posts: 91 Rep Power: 9 thank you for the hint urosgrivc, but is still doesn't work Although I selected Simplify, the geometry still generated NURBS when I imported it into the mesher. So I had to use my METHOD 2 (wing with many surfaces) and there were no more NURBS. Still, thank you for the suggestion, I learned something new

 Tags cfx, flow, mesh, nurbs, wing