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-   -   Master Degree Grid/Mesh Generator (https://www.cfd-online.com/Forums/main/98626-master-degree-grid-mesh-generator.html)

mechiebud October 22, 2015 14:58
Yes you are right.

mechiebud October 22, 2015 15:13
Quote:
Originally Posted by jchawner (Post 569677)
I just want to be certain of the terms you're using. The hyperbolic PDE method generates the points. An elliptic PDE method smooths existing points. So the way you describe it, you'd generate your mesh first with the hyperbolic PDE method and then apply an elliptic PDE method to a subset of that mesh in order to increase smoothness.
Yes you are right. So do you have any idea whether it will improve the mesh in any way.

ibluesun October 22, 2015 17:56
Hello Mechi,

unfortunately I didn't use the hyperbolic method in my meshing software.


However, John indeed have a deep experience in this topic. and I'm really enjoying his replies.

mechiebud October 23, 2015 03:01
Quote:
Originally Posted by ibluesun (Post 569722)
Hello Mechi,

unfortunately I didn't use the hyperbolic method in my meshing software.


However, John indeed have a deep experience in this topic. and I'm really enjoying his replies.
Hi Ahmed
Thanks for your response.

mechiebud October 27, 2015 02:09
Quote:
Originally Posted by jchawner (Post 569634)
Hello Mech:

Do you want to include elliptic smoothing within the hyperbolic formulation so it's applied as the grid is marching out? Or do you want to apply it after the fact?

If the former, I have no idea. Your best approach within the hyperbolic method is to properly implement all the smoothing controls.

If the later, see Thompson's book on structured grids which is freely available online.
Hello John. Could you please tell that in generation of elliptic grids we mostly mak the cut at the trailing of the airfoil. Can we do that at the leading edge.Will it affect the mesh generation?

jchawner October 27, 2015 08:03
You can put cuts (assuming you're talking about an O-grid topology) wherever you want. It's just topology and has nothing to do with the generation of the grid itself via the elliptic PDE method.

Also, you could just as easily use a C-grid or H-grid toplogy.

mechiebud October 27, 2015 09:01
1 Attachment(s)
Quote:
Originally Posted by jchawner (Post 570507)
You can put cuts (assuming you're talking about an O-grid topology) wherever you want. It's just topology and has nothing to do with the generation of the grid itself via the elliptic PDE method.

Also, you could just as easily use a C-grid or H-grid toplogy.
Thanks for your response sir.
But I am facing a problem in generation of ellipti grid. As I itererate my grids move away from outer boundary. I have attached the image file. Could you please guide me furthur.

jchawner October 27, 2015 09:15
I have no idea what's causing that and honestly it looks like a bug. But you've now opened the issue of control functions for the elliptic PDEs other than Laplace's equation which tends toward smooth isotropy. My suggestion is to look at Thompson's book.

Sarang V October 27, 2015 15:32
Automated mesh generation
 
Hi Ahmed,

Cheers for attempting a difficult problem. As some of them have suggested, the main problems are meshing complex moving geometries. For example, I.C Engine valves and cooling holes in gas turbines. Additional problems arise when you try to add refinement in these cases. That being said, there are commercial programs that take a shot at doing this. For example, CONVERGE CFD can mesh complex moving geometries automatically using a cut-cell cartesian method. In addition to this the software also supports automatic mesh refinement based on the gradients in the solution.

Now in your efforts what classes of problems are you trying to solve ? This is a big question that you need to ask in-order to formulate a work-plan.

Thanks,
Sarang

mechiebud October 27, 2015 16:52
Quote:
Originally Posted by jchawner (Post 570507)
You can put cuts (assuming you're talking about an O-grid topology) wherever you want. It's just topology and has nothing to do with the generation of the grid itself via the elliptic PDE method.

Also, you could just as easily use a C-grid or H-grid toplogy.
Quote:
Originally Posted by jchawner (Post 570518)
I have no idea what's causing that and honestly it looks like a bug. But you've now opened the issue of control functions for the elliptic PDEs other than Laplace's equation which tends toward smooth isotropy. My suggestion is to look at Thompson's book.
I looked into Thompson but couldn't figure out the problem. Can I get any sample code for elliptic grid generation over airfoils?
Thanks


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