|
[Sponsors] |
September 20, 2012, 03:17 |
How to tackle this problem?
|
#1 |
Senior Member
Join Date: Mar 2011
Location: Germany
Posts: 552
Rep Power: 20 |
I need to mesh the simple rectangular wing using Unstructured Mesh. I have to set finer node distributions near the leading edge all along the span. There is only one surface on suction side(upper), one surface on the pressure side(lower) and one surface in the wing tip region. I have set the finer node distribution on wing root curves and wing tip curves(shown in images) to get finer bunching on the leading edge but only these curves(wing root curve and wing tip curve) are respecting the finer node distribution not the whole span(from root to tip) as shown in attached images. I think I need to do some geometry operations on the upper and lower side of wing to tackle this problem but I have no idea about these operations. So how to tackle this? Thanks
Waiting for expert opinions of Diamondx and Simon Regards |
|
September 20, 2012, 03:55 |
|
#2 | |
New Member
R. Manigandan
Join Date: Jul 2012
Location: Pune
Posts: 5
Rep Power: 14 |
Quote:
1. in Global mesh parameter -> Volume meshing parameters->reduce the edge criterion try it once or 2. sweep the surface mesh by Edit mesh-> Extrude mesh-> select mesh-> Give volume element name->give ->side surface mesh name->topsurface mesh name on tht time you can the on two side will be tri surface mesh and top and bottom side quad mesh on it |
||
September 20, 2012, 05:37 |
|
#3 | |
Senior Member
Join Date: Mar 2011
Location: Germany
Posts: 552
Rep Power: 20 |
Quote:
|
||
September 20, 2012, 09:50 |
|
#4 |
Super Moderator
Ghazlani M. Ali
Join Date: May 2011
Location: Tokyo, Japan
Posts: 1,385
Blog Entries: 23
Rep Power: 29 |
what do you mean by geometry reparation, splitting the upper and bottom surfaces ?? i'm not much of an expert when it comes to unstructured mesh ! i can help you with geometry changing tough
|
|
September 20, 2012, 10:04 |
|
#5 |
Super Moderator
Ghazlani M. Ali
Join Date: May 2011
Location: Tokyo, Japan
Posts: 1,385
Blog Entries: 23
Rep Power: 29 |
i have a memory of a similar thread, may be you can find if make and advanced search, filter prefix "icem" and look for wing unstructured.... may be ...
|
|
September 20, 2012, 11:27 |
|
#6 | ||
Senior Member
Join Date: Mar 2011
Location: Germany
Posts: 552
Rep Power: 20 |
Quote:
Quote:
|
|||
September 20, 2012, 11:31 |
|
#7 |
Member
Yon Han Chong
Join Date: Jun 2012
Posts: 77
Rep Power: 14 |
Try adding density to the leading edge line.
Mesh -> Create Mesh Density In fact, if you go to the Ansys help on Create Mesh Density, it has leading edge on wing example. In that example, the density line was created in front of the leading edge but, in your case, you can just use the line dividing the upper and lower surface. |
|
September 20, 2012, 11:41 |
|
#8 | |
Senior Member
Join Date: Mar 2011
Location: Germany
Posts: 552
Rep Power: 20 |
Quote:
|
||
September 20, 2012, 11:51 |
|
#9 |
Member
Yon Han Chong
Join Date: Jun 2012
Posts: 77
Rep Power: 14 |
If you use the patch independant option the shell mesh will be affected as ICEM uses Octree volume mesher to create volume and surface mesh together and delete the volume mesh to leave the surface mesh.
If you use the patch dependant option then the density box will not do anything as the shell mesh is generated using surfaces. |
|
September 20, 2012, 13:26 |
|
#10 | |
Senior Member
Join Date: Mar 2011
Location: Germany
Posts: 552
Rep Power: 20 |
Quote:
|
||
September 22, 2012, 20:53 |
|
#11 |
Senior Member
Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
Posts: 2,663
Blog Entries: 1
Rep Power: 47 |
Some users like to run iso parametric curves along curving surfaces like this (or along fillets) to control the way the nodes fall... I am guessing that is what you are looking for.
Go into Geometry (tab) => Create/Modify Curves => Create Iso-Parametric curve... (or something similar to that, I don't have ICEM up to check the command) An iso parametric curve is one that follows the UV space of a surface. If you set it to 0.5, it will create a curve exactly down the middle of the surface. In your case, you might want to try 0.05 (or 0.95) to get it just 5 percent from the edge... You may even want to create a few of these near each other... If the curves are perpendicular to what you expect, then switch between u and v. Then when you generate octree tetra mesh, it will be controlled by the curves... It is sort of like forcing the tetras to line up along the leading edge of the wing. The downside is that the curves also constrain the smoother, etc. so you could have some reduced quality (but still good enough). Post a pic when you are done so people can see what this did for you.
__________________
----------------------------------------- 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 |
|
September 23, 2012, 03:18 |
|
#12 | |
Senior Member
Join Date: Mar 2011
Location: Germany
Posts: 552
Rep Power: 20 |
Quote:
|
||
September 23, 2012, 09:59 |
|
#13 | |
Super Moderator
Ghazlani M. Ali
Join Date: May 2011
Location: Tokyo, Japan
Posts: 1,385
Blog Entries: 23
Rep Power: 29 |
Quote:
there is a very handy tool there, you can create point depending on a parameter of a curve, 30%=0.3 50%=0.5. when you create your point, you can project that point to several other parallel edges again using the option "project point on curve". once projected, create an edge with those point, then slice the surface using those edge in the option "split surface using edge" i hope it can help. |
||
September 23, 2012, 19:52 |
|
#14 | |
Senior Member
Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
Posts: 2,663
Blog Entries: 1
Rep Power: 47 |
Quote:
You don't need to cut the surfaces for it to work.
__________________
----------------------------------------- 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 |
||
September 24, 2012, 10:50 |
|
#15 | |
Senior Member
Join Date: Mar 2011
Location: Germany
Posts: 552
Rep Power: 20 |
Quote:
|
||
September 24, 2012, 12:13 |
|
#16 |
Senior Member
Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
Posts: 2,663
Blog Entries: 1
Rep Power: 47 |
Octree tetra uses the patch independent method... In fact, Octree tetra starts with the volume mesh (it is a top down method) and then figures out the surface mesh from there.
When you start with a patch conforming method, it actually generates the patch independent mesh as part of its process and then dumps it to make the octree volume mesh conformal with the surface mesh. This really combines the worst of both worlds, like having German Police and French Mechanics, instead of the other way around. There isn't really much good reason to do all the work required to get a good patch conforming surface mesh if you are going to fill it with Octree... The one good exception is when you have just a few patch conforming surfaces (perhaps coming from an adjacent model) that you want the octree to align with. Octree would then create all the other surface mesh that you need... But in the end, I might still delete the octree mesh, smooth the surface mesh (alternating rounds of laplace and regular smoothing, ending with regular smoothing) and regenerate the volume mesh with a Delaunay Fill (with the TGlib and AF options). In your case, patch conforming mesh on the difficult thin surfaces may be easier than octree (PI surface mesh) and then you can fill with delaunay. If you have trouble with other surfaces in the model, just skip them with PI, and use Octree to capture them...
__________________
----------------------------------------- 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 |
|
September 25, 2012, 04:39 |
|
#17 |
Senior Member
AB
Join Date: Sep 2009
Location: France
Posts: 323
Rep Power: 22 |
You are right, German Police is awful
|
|
October 3, 2012, 09:31 |
|
#20 |
New Member
R. Manigandan
Join Date: Jul 2012
Location: Pune
Posts: 5
Rep Power: 14 |
Contact me in my mail ID manirainbow61@gmail.com i can help u from thr.
|
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
UDF compiling problem | Wouter | Fluent UDF and Scheme Programming | 6 | June 6, 2012 05:43 |
Gambit - meshing over airfoil wrapping (?) problem | JFDC | FLUENT | 1 | July 11, 2011 06:59 |
natural convection problem for a CHT problem | Se-Hee | CFX | 2 | June 10, 2007 07:29 |
Adiabatic and Rotating wall (Convection problem) | ParodDav | CFX | 5 | April 29, 2007 20:13 |
Is this problem well posed? | Thomas P. Abraham | Main CFD Forum | 5 | September 8, 1999 15:52 |