|
[Sponsors] |
October 14, 2011, 11:22 |
2D hybrid grid around high-lift airfoil
|
#1 |
New Member
Bastian Nebenfuehr
Join Date: Feb 2010
Location: Sverige
Posts: 27
Rep Power: 16 |
Hello everyone,
I'm trying to create a grid around a three-element high-lift airfoil. In principle, I would like to have an unstructured grid, but with some structured regions in it. For example, I want to resolve the boundary layers with a structured approach and maybe some smaller regions between the elements. So, I admit that this is not entirely a new problem here. I think I would have to take a similar approach as done already in this thread here: http://www.cfd-online.com/Forums/ans...ary-layer.html What I have tried, is the following: 1) I define a lot of small surfaces in the entire domain, on which I put a "2D surface blocking". Then I specify the respective surfaces to be either "mapped" or "free" with "all quads" or "all tets". This works, but seems very cumbersome, not to mention that the grid quality is rather bad. 2) I also tried using a "2D planar" blocking from the beginning and using O-grids around my airfoil-elements. This works great for the boundary layers, but I did not manage to specify some blcoks being structured and others unstructured. So, I think an intermediate approach would be ideal, but I did not manage to combine a "2D surface blcoking" with a "2D planar". It seems like they cannot coexist, if I chose one of them, the other one disappears. What would be your recommendations or what is the approach to pursue? Any comments will be greatly appreciated! /Bastian Ps: Unfortunately, I cannot post a picture of my geometry here, but just to get an idea, of what kind of thing I'm talking about, look here: http://people.nas.nasa.gov/~rogers/pegasus/images/fig1.jpg |
|
October 15, 2011, 09:48 |
|
#2 |
Senior Member
Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
Posts: 2,663
Blog Entries: 1
Rep Power: 47 |
I would use 2D Planar and split the blocks to get what you need... Have you seen the Youtube video (yours would need extra splits to separate out the flaps and slats and then you would only delete the blocks in the solid regions...) This is the link to part one of three...
http://www.youtube.com/ansysinc#p/u/37/tYrbScUH9RE If you already have the geometry, you can skip the geometry creation portion... Once the model is blocked out, you could convert far field blocks to unstructured triangles if you like...
__________________
----------------------------------------- Please help guide development at ANSYS by filling in these surveys Public ANSYS ICEM CFD Users Survey This second one is more general (Gambit, TGrid and ANSYS Meshing users welcome)... CFD Online Users Survey |
|
October 27, 2011, 02:59 |
|
#3 |
New Member
Bastian Nebenfuehr
Join Date: Feb 2010
Location: Sverige
Posts: 27
Rep Power: 16 |
Hi,
thanks for the reply. I still have not yet found the time to test this properly, but I remember last time I tried, I had trouble converting the blocks into unstructured blocks. Even though I convert the blocks into "free" blocks, I still got "quad" elements. What is the trick to get only "tri" elements? For the rest, I knew the video, but thanks anyhow, it's extremely helpful! Best, Bastian. |
|
October 28, 2011, 07:13 |
|
#4 |
New Member
Bastian Nebenfuehr
Join Date: Feb 2010
Location: Sverige
Posts: 27
Rep Power: 16 |
Now I made a test with a 2D planar blocking around my airfoil. It works quite nicely, but I still am not able to create blocks that are only producing tets. How do I do that?
Thanks, Bastian. |
|
October 28, 2011, 10:41 |
Free Face Mesh Type
|
#5 |
Senior Member
Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
Posts: 2,663
Blog Entries: 1
Rep Power: 47 |
After making a block "free", the mesh defaults to quad with (up to) 1 tri.
You need to go in and set the "Free Face Mesh Type" to "All Tri" if that is the sort of paving that you want... FreeFaceMeshType.jpg
__________________
----------------------------------------- Please help guide development at ANSYS by filling in these surveys Public ANSYS ICEM CFD Users Survey This second one is more general (Gambit, TGrid and ANSYS Meshing users welcome)... CFD Online Users Survey |
|
October 28, 2011, 10:43 |
Quad Dominant
|
#6 |
Senior Member
Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
Posts: 2,663
Blog Entries: 1
Rep Power: 47 |
__________________
----------------------------------------- Please help guide development at ANSYS by filling in these surveys Public ANSYS ICEM CFD Users Survey This second one is more general (Gambit, TGrid and ANSYS Meshing users welcome)... CFD Online Users Survey |
|
October 30, 2011, 06:22 |
|
#7 |
New Member
Bastian Nebenfuehr
Join Date: Feb 2010
Location: Sverige
Posts: 27
Rep Power: 16 |
Thanks again. Now I was able to create a mesh in the way that I wanted. It only needs a little (well, actually a lot) of fine tuning.
|
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Lift and Drag Coefficient data for NACA 2412 Airfoil | mahbub03 | Main CFD Forum | 22 | May 25, 2014 15:39 |
Lift and drag coefficient with strange values for NACA airfoil | antonio_ing | OpenFOAM Running, Solving & CFD | 16 | September 13, 2012 12:21 |
Help! Validity of unstructured grid on S809 airfoil | didiean | FLUENT | 11 | April 3, 2011 02:10 |
Airfoil simulation in High Angles of Attack | Yasser Nabavi | FLUENT | 0 | April 21, 2006 17:28 |
Airfoil Lift and Drag | Dr. Laith K. Abbas | Main CFD Forum | 8 | July 2, 2005 03:32 |