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This is an old revision of this page, as edited by Otr500 (talk | contribs) at 17:55, 27 February 2023 (Add "Article issues and classification" section and reassess article.). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

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Problems with the article

Why is there not any mention of LES(large eddy simulation) or DNS(direct numerical simulation) (fixed)

More importantly, what about Langrangian Techniques? Don't you think that Lagrangian and Euler based methods deserve a say in this article?

I think that there should be an introduction to the difference between the Lagrangian and Eulerian approach and how Lagrangian ones are better suited to handle interactions with rigid bodies (that are usually modelled with a Lagrangian approach). Lagrangian-Eulerian methods are also used widely in the field of CFD for computer graphics, where the main problem is the fluid-solid (and vice-versa) interaction and the free surface between the fluid and the air (that's the visible part of fluid flow, so it's important for CG). Maybe a reference to the level-set method is also needed as it is a link to this book http://www.cambridge.org/us/catalogue/catalogue.asp?isbn=0521853109

Added 5/1/2005 I've cleaned the article up a bit, and pointed out the key issues with regard to discretization at the very beginning. User:Rtfisher

In the article it says, "While it is possible to directly solve the Navier-Stokes equations for laminar flow cases, turbulent flows require the introduction of a turbulence model."

This is not true since DNS does not use any turbulence model, although it solves the Navier-Stokes equations directly.

"Boundary conditions are defined. This involves specifying the fluid behaviour and properties at the boundaries of the problem. For transient problems, the initial conditions are also defined"

This is not true since initial conditions are specified for steady-state problems as well. In steady state problems, the solution evolves from the intial guess to the final steady state solution.— Preceding unsigned comment added by 134.117.175.33 (talk) 05:21, 17 November 2004 (UTC)[reply]

In that case it isn't an initial condition, it's an initial guess. By definition, initial conditions are the conditions for when the time coordinate is equal to zero. If there is no time coordinate, there cannot be initial conditions. So the statement is correct. --Charlesreid1 (talk) 00:10, 5 November 2010 (UTC)[reply]

There is probably no mention of LES because because nobody felt competent to write it. It's not exactly a well-known subject. I worked in the field, and I'm not competent. Feel free to add what you know. Be bold in editing. DJ Clayworth 04:00, 18 Nov 2004 (UTC)

The "Boussinesq hypothesis" link that is included under the RANS subsection should refer to Boussinesq's assumption regarding a scalar eddy viscosity and not to his approximations regarding buoyancy-driven flows. 129.22.149.57 20:38, 18 April 2007 (UTC)[reply]

Patankar?

Does Suhas Patankar warrant a mention in this article? If so, could someone more knowledgable than I whip up a sentence to do so. Thanks. -- John Fader 21:27, 17 Feb 2005 (UTC)

We need, I think, a paragraph or two at the beginning that explains CFD for the layman. Someone with no mathematical background coming to find out what CFD is all about needs some information before we start getting into discretization method. It should go first because if they don't get something they understand in the first paragraph they will stop reading. DJ Clayworth 11:20, 3 May 2005 (UTC)[reply]

I disagree, I think some mention of the most common discretization methods (a sort of "where to go" if you're interested in discretization methods) is definitely called for in the article (although I agree it doesn't belong in the introduction). For example, Patankar would be an excellent reference for the control volume subsection of the discretization section. Finite volume, finite element, and particle methods would also be good to mention, since most discretization methods in use fall into one of these four categories. If someone is qualified to add brief descriptions of another discretization method, that would be great. In any case, each would be a short description linking to a main article. --Charlesreid1 (talk) 00:13, 5 November 2010 (UTC)[reply]

Separate articles about the turbulence models

Perhaps the sections about turbulence models (DNS, RANS, LES) should be integrated more with their respective separate articles, to avoid having the same information in more than one place? -- Ehdr 15:33, 16 March 2007 (UTC)[reply]

The general approach should be to give a brief description of each turbulence model, as it pertains to computational fluid dynamics, and use the {{Main}} template to point readers toward the full article if they're interested. --Charlesreid1 (talk) 00:16, 5 November 2010 (UTC)[reply]

Cleanup templates

I've gone through and added multiple cleanup templates, particularly {{Refimprove}}, {{Unreferenced section}}, {{Weasel}}, {{Who}}/{{Whom?}}, {{Citation needed}}. The style of writing in the article is terrible, it sounds more like an editorial than an encyclopedic treatment of CFD. The sections could be greatly improved by simply adding some additional references and getting rid of weasel words and editorial phrases, but more work is sorely needed. It's frustrating to see such an important topic get such a poor treatment. --Charlesreid1 (talk) 18:04, 5 November 2010 (UTC)[reply]

Quality of article and references has seen a marked improvement. Charlesreid1 (talk) 10:13, 31 March 2017 (UTC)[reply]

Lowering Article Quality Rating

I've lowered the article quality from C to Start due to the lack of citations and overall plethora of unverified claims. I'm also including the Wikipedia editorial team's assessment table/criteria below. I believe this article very clearly fits in the Start class, as it lacks citations, has had a {{Refimprove}} template since 2008, and leaves a majority of readers looking for a different source of information about CFD.

Accordingly, the number one task for improving this article should be to include additional references for unverified claims.

{{Grading scheme}}

--Charlesreid1 (talk) 18:13, 5 November 2010 (UTC)[reply]

Revisiting the article rating, as the quality of this article has substantially improved over the years. The rating now seems to fit best in the B category. In keeping with WP:BOLD, changing article rating to B. Charlesreid1 (talk) 10:01, 31 March 2017 (UTC)[reply]

Huh?

This article states: "With high-speed supercomputers, better solutions can be achieved." This would imply that merely switching to a faster computer is going to help, which is of course not true. Higher mesh resolution will generally help get a "better" solution as will improving physical models - both of these require more computational resources, so if you want to get your answer in the same time, you'll need a faster computer, but a faster computer will not in itself do much for you in terms of accuracy, assuming that's what "better" is supposed to mean here.— Preceding unsigned comment added by 192.158.61.141 (talk) 14:58, 25 May 2011 (UTC)[reply]

Combustion models for CFD

Can someone review this newly created article? Not sure if it should be a stand alone. Hell In A Bucket (talk) 13:56, 4 December 2012 (UTC)[reply]

CFD in Aerospace Accident Investigations

Does someone know if CFD is regulary used in Aerospace accident investigations. I read about CFD investigations related to space missions, but is it typically used for investigations within the aerspace domain? — Preceding unsigned comment added by 195.124.114.42 (talk) 15:24, 12 August 2013 (UTC)[reply]

Merge with Fluid simulation

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.
The result of the discussion was not to merge the Fluid simulation article into the Computational fluid dynamics article. Charlesreid1 (talk) 10:06, 31 March 2017 (UTC)[reply]

I see no clear distinction between this article and the article Fluid simulation, so I propose that we merge them together. What do you say? —Kri (talk) 19:10, 18 September 2014 (UTC)[reply]

  • Oppose These are different topics. CFD is about numerically solving the equations of fluid dynamics as well as possible. Fluid simulation in computer graphics is about simulating the appearance of fluid elements in a graphics scene or animation. If a fluid simulation looks good, it doesn't matter if the physics is correct. An example of this is Fourier synthesis of ocean waves. This technique can produce a good looking ocean, but isn't numerically solving the underlying equations of fluid dynamics. --Mark viking (talk) 17:55, 25 September 2014 (UTC)[reply]
Well, I would say that the Fourier synthesis is a form of CFD and that it does solve the underlying wave equations approximately after making some assumptions about the flow, since it is based on theory, which is really what all other CFD methods do as well. :) Although it is not a very powerful method and can only be applied to a very limited set of fluid dynamics problems, like those that are interesting in computer games and computer graphics. —Kri (talk) 20:51, 25 September 2014 (UTC)[reply]
Respectfully, I disagree. As the Mastin, et. al., 1987 paper on Fourier synthesis of ocean waves describes, this particular fluid simulation is based on Fourier synthesis using a weighting based upon a Pierson–Moskowitz spectrum. The spectrum itself is an empirical, statistical one derived from ship wave data. While there is simulation of the appearance an ocean surface, there is no underlying numerical simulation of any equations of fluid dynamics. Mastin, et. al., were faking it and doing a good job of it--it was a big advance in computer graphics. But it wasn't CFD. --Mark viking (talk) 23:56, 25 September 2014 (UTC)[reply]
The Fourier synthesis method uses a differential equation to update the phase angle in the Fourier transform of the free surface elevation. This equation can be derived from the boundary element method applied to incompressible, irrotational ocean water, by linearizing the boundary integral equation and transforming it to the frequency domain. This results in that different eigenmodes map against different wavevectors. If this is not CFD, where along the transformation from BEM does it stop being CFD? When does the differential equation stop being an equation of fluid dynamics? —Kri (talk) 10:53, 27 September 2014 (UTC)[reply]
About the usage of a spectrum, that just affects the initialization of the system, so I don't see how that would affect the method itself. —Kri (talk) 11:10, 27 September 2014 (UTC)[reply]
  • For: The only difference that might exist between the terms "CFD" and "fluid simulation" is in the way they are normally used, and would in that case be (as XFEM Skier pointed out) their goals. Although essentially, they are two different terms for the same concept—they both simulate fluids by solving fluid dynamics equations numerically and can both utilize the same methods (even though the usability of the different methods may vary depending on the goal). Sure, CFD is a branch of fluid mechanics, but fluid simulation may also be seen as such. The two terms also seems to be used interchangeably by Jerry Tessendorf in a TED talk I recently bumped into. —Kri (talk) 17:49, 19 November 2014 (UTC)[reply]
  • Oppose Arguably fluid simulation (in the sense used here) is a subtopic of CFD, but even taking that to be correct, if they were merged into one article then I would suggest splitting the computer graphics part of the merged article off into an article of its own. The amount of content in the current fluid simulation article is over the top for its significance in CFD, it's sufficiently notable for an article of its own, so it should continue to have one. Djr32 (talk) 19:37, 26 December 2014 (UTC)[reply]
  • Oppose Fluid simulation and CFD are essentially synonyms. The current 'fluid simulation' article should be re-titled to something more appropriate and descriptive, e.g. 'fluid animation' or 'fluid simulation in computer graphics' or something along those lines. Christopherbatty (talk) 01:42, 23 February 2016 (UTC)[reply]
  • Oppose Fluid simulation and CFD are basically the same thing. However, I agree that the current fluid simulation article has the wrong name and should be called fluid animation (or something similar) instead. I'll probably do the rename in a few days unless someone disagrees. ArguMentor (talk) 11:46, 27 February 2016 (UTC)[reply]
You and Christopherbatty make a good point. I'd support a better fitting rename. --Mark viking (talk) 21:12, 27 February 2016 (UTC)[reply]
The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Parallel computing

This is missing from the solution methodology. I think it is an important and interesting item and is also one in the to-do list topics to include of this article. I propose a section with a few bullet points regarding

  • The need for parallel computing
  • Methodology
    • Shared vs. distributed parallel computing
    • Partitioning (principles and methods)
  • Various protocols (MPI, PVM, etc)
  • Best practices
    • Nodes/CPU core
    • Overlapping
  • Parallel performance definition
  • Massive parallel (thousands of CPUs)

I will soon drop a draft. Sankgeo 10:47, 14 March 2016 (UTC) — Preceding unsigned comment added by Sankgeo (talk • contribs)

Article issues and classification

Article fails the B-class criteria with several November 2010 "citation needed" tags and several unsourced (as yet untagged) paragraphs and subsections. Reassess article to C-class. -- Otr500 (talk) 17:54, 27 February 2023 (UTC)[reply]

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