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O-GRID generation in ICEM CFD

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Old   August 23, 2007, 16:09
Default O-GRID generation in ICEM CFD
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Mohammad Faridul Alam
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I am facing problem while genearting O-GRID around NACA0012 Airfoil.The problem is: the girdlines on the airfoil are not being perpendicular to the surface of airfoil. I need such mesh where each gridline will be perpendicular to the airfoil.

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Old   August 24, 2007, 03:18
Default Re: O-GRID generation in ICEM CFD
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Dr. Flow Squad
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You should probably go for a C-grid instead. Here's a late post with pictures showing two different block structures. http://www.cfd-online.com/Forum/cfx_...cgi?read=20096 -Dr. Flow Squad http://tinyurl.com/2gkjh8

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Old   August 27, 2007, 00:37
Default Re: O-GRID generation in ICEM CFD
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Mohammad Faridul Alam
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Thanks. I have seen the C-GRIDS. but still the grid lines on the airfoil are not normal to the surface of the airfoil. we are looking for perfectly normal gridlines on the airfoil.
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Old   August 27, 2007, 18:18
Default Re: O-GRID generation in ICEM CFD
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Glenn Horrocks
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Hi,

You can also get nice boundary layer meshes with CFX-Mesh with lots of inflation layers. You can also ensure the gridlines are normal to the airfoil this way too, but be careful at the trailing edge. It is tricky to get the trailing edge to inflate nicely.

Regards, Glenn Horrocks
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Old   December 11, 2009, 04:36
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Rauno
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So,
bottom line is that for an airfoil the O-Grid option (with ICEM CFD) could not be used, due to the topology?
I tried all the possible topology, but I wasn´t able to use the O-Grid option.
On the other hand, following the indication of previous post one can anyway obtain a good quality mesh using parameters (to have the grid perpendicular to thge surface).
Any other experience /suggestion about that?
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Old   December 11, 2009, 05:14
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Glenn Horrocks
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Well have a think about it - what will an O grid do at the sharp trailing edge? I will let you work it out from there.

The easiest way to make the grid perpendicular to the surface is to generate a small block at the airfoil surface with a thickness defined by a given normal distance from the airfoil. Then it is easy to do a very nice structured mesh on the airfoil surface, and you move the transition to the far field grid (with its associated poorer quality elements) away from the airfoil.

But with some care you should be able to get the mesh perpendicular to the surface with a standard C-grid. You will just need to look into the parameters and adjustments closely.
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Old   December 11, 2009, 15:40
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Thank you, your message was very instructive.
And yes, the O-grid wouldn't be the best solution, due to the sharp trailing edge.

However, I tried many different topology without been successfull in realizing an O-grid anyway.

Your suggestion is meaningfull and interesting. I fould it not so immediate, but this is surely due to my unexpertise with ICEM.
What I need is something not much complicated still of good quality, since I have to do many simulation on different airfoils.
I wasn't able to find, after a fast search here in the forum, the "best"" approach to mesh an airfoil. Thank you.
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