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-   -   Airfoil in ICEM (http://www.cfd-online.com/Forums/ansys-meshing/75616-airfoil-icem.html)

NDM1TSG April 30, 2010 12:15

Airfoil in ICEM
 
Hi
I'm trying to model a geometry and a mesh for an airfoil in ICEM, and regarding this I have two questions.
First one: I import the airfoil via the "formatted point data". Now I want to make three curves out of the points, the upper half, the down half and the trailing edge of the airfoil. I want to make all curves with the "arc through 3 points", because I think they are the smoothest curves, and then summarize alle the little curves to the three final ones. However, when I try to summarize them, I always get an error that tells something like "At location xxxx is a gap of 0.0000000 with a tolerance of 0.000000, curve not created" (or similar). What does that mean and how can I get the smooth curves I want?

Second question: When I use the "Curve through points" to make my airfoilcurve, I get an angled curve, but with this I tried to move on. I created an rectangular 3D control volume around the airfoil with the faces INLET, OUTLET, TOP, BOTTOM, FRONT an BACK. The airfoil itself is made of three faces and called WALL. Now I create a 2D planar block on BACK (but in the part SOLID) and do all my blocking.
After this I want to make the mesh 3D and write an output file to ANSYS CFX. But how do I make the mesh properly 3D so that I can define all boundary conditions in ANSYS? I tried "2D to 3D blocking" in the part SOLID and extruding the 2D mesh, but later in ANSYS, when I'm defining boundary conditions, I can't choose all the faces I created in ICEM (usually, TOP, BOTTOM, INLET und OUTLET are missing).

Thank you very much for your answers!

Anonymized_JL1 April 30, 2010 12:28

http://www.youtube.com/watch?v=tYrbScUH9RE
http://www.youtube.com/watch?v=EknKV...eature=related
http://www.youtube.com/watch?v=6wQPe...eature=related

NDM1TSG April 30, 2010 12:40

I alreday watched them, they dont help me. I import the points without a curve, if I do I just get one curve with a gap at the trailing edge (TE isn't one point, it has an edge).
Also the mesh is made 3D while writing the output file to FLUENT (I use ANSYS CFX) and not with a block or mesh option in ICEM itself.

PSYMN June 8, 2010 17:34

several ways
 
Associating edges to curves is particularly important for 2D Blocking.

If you properly associate the edges to the curves, then you get line elements in the parts of the curves (inlet, outlet, wall or whatever). Then if you do a 2D to 3D blocking extrude or, even easier, convert to 2D unstructured mesh and extrude that into 3D elements, your line boundaries will extrude into shells that you can use for 3D bocos...

But the easier way to handle it is just to keep it 2D and output in Fluent format. CFX has a feature where it automatically extrudes 2D fluent meshes during import so they can work in CFX.

As for the instructions, to handle the flat trailing edge, simply don't collapse the trailing edge block. Fan it out (fish tail) instead.

Simon


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