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Old   May 23, 2008, 13:30
Default DG introduction
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John
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I'm familiar with CG well (and FVM as well), but I do not have any knowledge about DG, can anyone suggest me a suitalbe an introductory reference (brief that gives concept)
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Old   May 23, 2008, 15:20
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Jed
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I like the sections on DG in Karniadakis & Sherwin `Spectral/hp element methods for CFD'. For elliptic problems, there are several inequivalent approaches with different stability, consistency, and computational properties. Arnold and others 2002 `Unified analysis of DG for elliptic problems' is a good start, but somewhat technical.
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Old   May 23, 2008, 17:47
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jinwon park
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B.Q. Li, 'Discontinuous Finite Elements in Fluid Dynamics and Heat Transfer', Springer 2005
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Old   May 25, 2008, 09:13
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Rami
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John,

I have received lecture notes from Bernardo Cockburn (cockburn@math.umn.edu), one of the major players in this field. You may contact him directly, or else send me your email and I'll forward it to you.

ami
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Old   May 25, 2008, 09:28
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John
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please forward a copy to me (john.dongarra@gmail.com), thanks.
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Old   May 25, 2008, 09:45
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Rami
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Please find it in your mailbox.
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Old   May 25, 2008, 11:27
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John
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Thank, but what you sent to me is not a Lecture note, but is a review paper, which is not useful for starter!

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Old   May 26, 2008, 09:45
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Rami
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Well, this is what I had from him. As a last help I can offer, have a look at this ppt presentation: www.iacmm.org.il/ISCM20/DGM_ISCM20T.ppt

Hopefully, this will be helpful.

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Old   May 26, 2008, 12:22
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John
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Thanks for your knid effort.
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Old   May 27, 2008, 02:23
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Rami
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You are welcome. If it does not serve your need, the cats pictures at least are cute...
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Old   August 2, 2011, 03:20
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Quote:
Originally Posted by Rami
;55274
John,

I have received lecture notes from Bernardo Cockburn (cockburn@math.umn.edu), one of the major players in this field. You may contact him directly, or else send me your email and I'll forward it to you.

ami
please forward a copy to me (shahzadakhurramkhan@gmail.com), thanks. as soon as possible because I am studying the Book "Discontinuous Finite Element For Fluid Dynamics and Heat Transfer" by Ben Q.Li. I think there are typing error so give the any useful material about DFEM. I am very thankful of you.
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Old   August 2, 2011, 03:25
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I've found the Book by Li not very good... why not try the Hesthaven book (has become standard in the field) or Kopriva's DGSEM? I find both of them to be much more readable as well---
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Old   August 2, 2011, 03:29
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Originally Posted by cfdnewbie View Post
I've found the Book by Li not very good... why not try the Hesthaven book (has become standard in the field) or Kopriva's DGSEM? I find both of them to be much more readable as well---
Book Name and Author Name DGSEM
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Old   August 2, 2011, 03:33
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sir, yes, sir!!


http://www.amazon.com/Nodal-Disconti.../dp/0387720650

http://www.amazon.com/Implementing-S.../dp/9048122600
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Old   August 2, 2011, 07:34
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For more and advanced information on modal DG method you can look the thesis of Landamann:

http://elib.uni-stuttgart.de/opus/vo...9/pdf/diss.pdf

Also, if you want to understand very well the dg method you must read by books or papers the below matters:

1.Schemes of finite volumes theory (due to relation of dg with finite volumes (discontinuity at interfaces-fluxes))
2.Riemann solvers (mainly approximate Riemann solvers)
3.Spectral & high order Elements
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Old   August 2, 2011, 09:25
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Originally Posted by panou View Post
For more and advanced information on modal DG method you can look the thesis of Landamann:

http://elib.uni-stuttgart.de/opus/vo...9/pdf/diss.pdf

Also, if you want to understand very well the dg method you must read by books or papers the below matters:

1.Schemes of finite volumes theory (due to relation of dg with finite volumes (discontinuity at interfaces-fluxes))
2.Riemann solvers (mainly approximate Riemann solvers)
3.Spectral & high order Elements
thanks I will Study these materials about DG.
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Old   August 2, 2011, 12:38
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Quote:
Originally Posted by panou View Post
For more and advanced information on modal DG method you can look the thesis of Landamann:

http://elib.uni-stuttgart.de/opus/vo...9/pdf/diss.pdf

Also, if you want to understand very well the dg method you must read by books or papers the below matters:

1.Schemes of finite volumes theory (due to relation of dg with finite volumes (discontinuity at interfaces-fluxes))
2.Riemann solvers (mainly approximate Riemann solvers)
3.Spectral & high order Elements
Well, in my opinion, most people nowadays tend to use nodal DG schemes, at least from what I know about some of the "big players" in the field.... but modal sure has its own advantages, so it's good to know at least the basics....
I'd still recommend DG SEM by Kopriva for a beginner...

Regarding the Riemann solvers: that depends on what you want to do with your code....
for well-resolved problems, the Riemann solvers shouldn't really matter at all, but for underresolved probs, I agree...

Cheers!
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Old   August 2, 2011, 16:18
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The choice of Riemann solver play important role for DG formulation. Is the way that an element derives information by neighbour elements.
Mainly for solutions with large gradients or discontinuities(such as shocks)
the Riemann solver is crucial part due to the resolution of solution at these regions.
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Old   August 2, 2011, 16:32
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Quote:
Originally Posted by panou View Post
The choice of Riemann solver play important role for DG formulation. Is the way that an element derives information by neighbour elements.
Mainly for solutions with large gradients or discontinuities(such as shocks)
the Riemann solver is crucial part due to the resolution of solution at these regions.
Hello panou, I tend to half-disagree with you )
Sure, Riemann solver couple the system, but due to the higher polynomial approximation in the cells, jumps at interfaces tend to be much smaller than for FV... Thats why you can get away with using a cheaper Riemann solver than FV. In fact, as long as you are decently resolved, lax Friedrichs is ok most of the time!

Regarding shock capturing: shocks on coarse grids are generally not captured at the grid cell interface, but within the cell!! And thats done by stabilizing with viscosity, not by the Riemann solver.


So, as you see, in DG Riemann solvers play a less important role than in FV!

Cheers!
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