Airfoil mesh recommended way
 

Hi all,
I am new to CFD and working on a project to analyse wind tunnel data for small UAV aircraft and compare it to results from CFD simulation.
I am starting by just comparing the wing wind tunnel data. I have been going through the cornell airfoil tutorial and think this is the best place to start and then I can use my wing and follow the same approach.
I am using Ansys 12.1 workbench and as Gambit is no longer used , I been trying to follow the tutorial using ICEM CFD. I am just about getting there, imported points ,create curves, create surfaces and now I am setting the point distribution for each of the edges for the mesh.
My question is, am I going about it the right way in creating the mesh Should I :
1) carrying on trying follow instructions for Gambit for ICEM CFD?
2) Use blocking to create the mesh?
3) Use desginmodeler then ansys mesh?
4) Use Ansys 11 so I can use Gambit to create mesh?

I hope too create a 3D model of the UAV and analyse the results as part of the project , its all a bit overwhelming trying to learn how to use Ansys.

Different...
 

Gambit and ICEM CFD use totally different approaches...

All you should carry over is the concept of topology... You ultimately need a good blocking topology and I have found that Gambit users are quite natural with ICEM CFD once they understand that the method to create that topology is very different.

That difference is that in Gambit you chop up the geometry and try to sweep your way thru it.

In ICEM CFD, you use a separate layer of "Blocking" that is much easier to chop up (especially for boundary layers) and has patch independence...

Try some tutorials, visit the Demo room, etc.

http://www.ansys.com/demoroom/

Can anyone send me that tutorial ibzyuk is talking about?

Maybe I could write up the ICEM CFD steps to help some people migrate.

Simon

This is the Tutorial of a 2D Airfoil Meshing and Simulation from Cornell University. please follow the link http://courses.cit.cornell.edu/fluent/airfoil/index.htm

Oh! Great! Thank you so much for your material:)

Thank you very much PSYMN it would be great for a similar tutorial for ICEM CFD it would really help migrating across from Gambit and learn about blocking.
I will start looking at blocking and check out the Demo room. What I was doing was setting the point distribution for my edges then running the create surface mesh. Will this not work?
I was wondering will ICEM CFD also be removed from Ansys in the future as it will be incorporated as part of Ansys Mesh?

Finally...
 

I FINALLY made a "how to" movie to answer this frequently asked question, well three parts actually.

They are on the ANSYS YouTube site...

http://www.youtube.com/ansysinc

I know it is late, but I hope it helps...

I think you will find that it is similar to the Cornell tutorial... I even started with the same airfoil and in the same format, except I had more points in my file...

Hi Simon,
Thank you so much for providing us with a great Video of airfoil meshing. I am done with my rotating mesh of 2D airfoil and even I am now able to simulate it but having some problems regarding the mesh smoothing near the airfoils edges. it would be great if you could just have a look at what I have done just to check it.

Thank you very much
 

Hi Simon,
Thank you for the excellent tutorial . It has helped me understand blocking much better . Will be giving it ago and will let you know how it goes.


Thanks again,

Ibrahim

I can not connet to that site. could you given me another link to you video?
thanks a lot.

send me your email and than i will send you the file

ftp links...
 

I posted it here for someone else on another thread back on 4/19/10...

ftp://ftp.ansys.com/outgoing/simon/2...l_1_Slides.avi

ftp://ftp.ansys.com/outgoing/simon/2...il_2_Setup.avi

ftp://ftp.ansys.com/outgoing/simon/2...l_3_Replay.avi

Best regards,

Simon

applying to 3d
 

Hello, what a great tutorial for ICM , Thanks!

I am wondering how I can apply this to 3d in ICEM for LES of an airfoil. I've played around with it for to long and am getting nowhere.

Thanks

Brian

p.ke@163.com
thanks a lot!

I am a little swamped right now, but will post a 3D version when I have the time...

I understand, everyone seems busy this time of year. I followed the wing body tutorial in ICEM. Did the blocking and created an ogrid around the airfoil. I seem to have a nice surface mesh, but getting the same surface mesh translated into a volume mesh has not been good. Also I am a bit confused about: should inlets, pressure outlets, ect. be parts or surfaces.
Also what should the mesh size be for LES. I have been looking at Fluent help and mentions something for "Best Practices for LES".

It seems like I am close but just need to get over the hurdle. We need have the simulation done by Monday for a presentation:) If I cant mesh it a teammate might try Gambit.

Thanks again.

Brian

Pass it thru
 

If you have an collapsed trailing edge, it is often best to extend that block collapse out to the far field...

Imagine the 2D I showed, but do that all the way from the fuselage or wall out to the far field...

Usually, I create a CGrid around the wing (out the back of the far field) and an Ogrid around the fuselage (intersecting the CGrid) and then do my collapse...

Simon

Thanks for the reply Simon.


I am just modeling a airfoil section only with collapsed trailing edge, no fuselage. I took the ff shape of your video and just gave it a thickness. the wing span is 0.5c( attached to wall) while the thickness is 5c. I am not sure how create a C grid in 3d? I just created a block around the wing section, then created ogrid. I am also wondering should the inlet and outlet, symmetry, wing be parts or surfaces? Should the thickness be a part, ,Live? The surface mesh kind of extends through the volume in some parts. I will try to figure out how to attach picture.

Create surface mesh first, then volume, ect? I am poor college student, but willing to pay for education:)

thanks again,

Brian

C-Mesh, ICEM Tutorial, Extrude to 3D
 

Hi everybody,

I literally followed the Tutorial (from Simon), which I have to say is very helpful. Esspecially when you realise you have missed one click, not allowing you do get the C-mesh working. Thank you very much.

I use CFX and ICEM 10.0. When I created the mesh in 2D I thought, I can just extrude it by one cell (after converting to unstruct mesh).
This worked perfectly, but now comes the problem.
I do not know how I can set the Boundary conditions after extruding it. Before I set up the whole problem as 3D (automatic generated mesh) and could just set the boundary condition in CFX Pre, from the surfaces in different parts. Here I used the solver ANSYS CFX, as it was the only one that worked for me as the other ones had error messages as "child process aborted".

Could please anyone tell me how this can be solved?

Thank you in advance.

Karatix

I too extruded the 2d mesh, and tried to name faces of the mesh, for fluent bc, but it doesnt recongize them.

Mayday, sos, my ship is sinking fast.

Thanks

Brian