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Jonas Larsson September 10, 2005 07:06

CFD Wiki - We Need More Help
We are a few volunteers who have started work on a CFD Wiki here at CFD Online. Before we launch it publicly as a part of CFD Online it needs some basic content and structure. We need more people to help us with this though! You can write about anything CFD related, any contribution is welcome. Just pick a subject that you are familiar with and add something. It can be just a few words and a definition or it can be a whole article describing a turbulence model or even a best practise guideline.

Here are a few examples of what the Wiki will be used for:

* A CFD textbook - Including an introduction to CFD, basic fluid dynamics, governing equations, turbulence modeling, numerical methods, discretizaition schemes, solvers etc.

* Best Practise Guidelines (both general and application/topic specific)

* FAQ's for various CFD codes, especially for the codes that already have forums here at CFD Online

* Validation/test cases - both description of suitable cases with data to compare with and contributed solutions

* Source code archive - free contributed codes, both CFD codes and smaller scripts etc. that are usefull for a CFD engineer.

To give you some inspiration on what you could help us with you can check out the following random examples of material that we recently added to the Wiki:

Favre averaged Navier-Stokes equations

Baldwin-Lomax model


Best practise guidelines for turbomachinery CFD

Gerris Flow Solver

Osborne Reynolds

Before you can contribute to the Wiki you need to register (click the link in the top right cornet). You might also want to read the help section and the community pages. You can find the main page of the Wiki here

Please don't hesitate to join our small team of of Wiki editors! We need your help!

Jonas Holdeman September 10, 2005 13:50

Re: CFD Wiki - We Need More Help
So, suppose one has registered with CFD-Wiki, and wants to prepare a non-trivial article off-line without downloading, installing, and learning a lot of software. Suppose this person can write using LaTeX, and maybe knows a little HTML. How does one go about preparing an electronic document offline for submission?

Jonas Larsson September 10, 2005 14:10

Re: CFD Wiki - We Need More Help
Well, the wiki understands basic latex (only math formula stuff though) and html (not everything, but most simple things). There is also some special wiki markup that you will need to learn. It is very simple though. You can find more info on wiki markup here:

To prepare a document off-line just write it in your favourite text editor, using latex, html and wiki markup wherever you need. Then when you are online just go to the wiki page where you think your article fits (or create a place where it fits) and then just cut-and-paste your document into a wiki article, preview and save it.

I hope that helps. Let me know if I you still wonder about anything. It takes some getting used to think in a "Wiki" way, but once you've got the hang of it it is trivial and fun. Don't feel that your article has to be complete and the final description of the subject... just write whatever you can and have time to, upload it to the Wiki, and leave it to someone else or you to improve it later. The Wiki is a dynamic document which lives and evolves continously.

M September 10, 2005 23:09

Please make sure that all material you add is free
I would like to try to prepare article about discretization schemes. Would it be a plagiarism, if I'll give the same description of (for example) HLPA scheme the same way as it was described originally by Zhu?

I said "try" because I am not so good in LaTex and it will be my first work with it... :)

Jonas Larsson September 11, 2005 05:06

Re: Please make sure that all material you add is
Without Zhu's permission you may not copy his entire article, or use large parts of his published text word-by-word. However, you may describe his scheme using the same equations and logic. Research results are not copyrighted, but the exact text in a published article usually is. You should of course also write a reference to Zhu's paper(s). I think that a good rule of thumb is that it is okay as long as you don't cut-and-paste large parts from his paper or re-write it exactly as he wrote it word by word.

I should also say that the Wiki is not the place to publish original research - that belongs in peer reviewed conferences and journals. The Wiki should be used to gather and collect already established research results that have been published somewhere else before.

I hope that helps.

About LaTeX, it is quite easy once you get the hang of it. For some examples of how to write equations and turbulence models in latex click on the "edit" button (after you have registered) on the following to pages:

These pages use quite a lot of latex (combined with a bit of HTML tables in order to number the equations - see the source). To get something to start with you can just cut-and-paste from these. For more help on latex you can also check out:

If you run into any trouble just email me ( or chat with me on msn ( or skype (cfdonline).

arbit September 11, 2005 06:16

Quality control ?
Any thoughts about quality control ? How can one evaluate the contents of such articles (with respect to scholarly content) ? It seems (atleast to me) that there is no dreath of people (read novices) who would be very keen on this.

Jonas Larsson September 11, 2005 06:33

Re: Quality control ?
Quality control is the responsibility of all users of the Wiki. If you find an error, please correct it. If you are unsure about something that you add to the Wiki, indicate this and write a short note that someone else ought to review this. If the Wiki becomes frequently used and grows quality will improve over time as more and more visitors "debug" the content and make it more complete.

The wiki software contains a lot of features to handle quality also - full revision control, moderation, "patrolling" of new modifications etc. As the Wiki grows we can also appoint reviewers of certain sections to help ensure the quality there.

Right now my worry is mainly to get content and a basic structure. Once we reach the turning point and the snow-ball hopefully starts rolling on its own I will focus on ensuring quality instead of expanding the content.

Fabian September 12, 2005 14:57

Re: CFD Wiki - We Need More Help
Hi all,

it would even be nice to see one 'global' nomenclature which is viewable in wiki format and downloadable in latex-format :)

Greetings! Fabian

Jonas Larsson September 13, 2005 04:30

Re: CFD Wiki - We Need More Help
Yea, I know :) I started a nomenclature section in order to at least try to coordinate our use of acronyms throughout this CFD Wiki. In case you haven't seen it already you can find it here:

It uses LaTeX for all the formulas but the page-layout has been wikified. It was in latex originally and I used a script to search-and-replace some latex stuff. It wouldn't be very difficult to use a similar script to "un-wikify" it into pure latex again.

Fabian September 13, 2005 07:32

Re: CFD Wiki - We Need More Help
Hi Jonas,

I saw it already :) A while back I started to write/use Stephen Pope's Nomenclature, but I never finished it. It was too much and I was hoping that anybody could share his latex-nomenclature. There should be a lot out there!

Greetings! Fabian

M September 13, 2005 16:51

CFD-Wiki may be edited, altered, or removed by oth
Dear Jonas

"Please note that all contributions to CFD-Wiki may be edited, altered, or removed by other contributors. If you don't want your writing to be edited mercilessly, then don't submit it here."

How it can be? This mean that anyone "bad boy" can delete a work of the hole community?

M September 13, 2005 17:10

Jonas it's very dangerous
Today I logged into the Wiki and discovered, that everyone can completely delete the work of the hole community. Please make something. Otherwise it isn't worth to write in Wiki.

I offer next. If someone decide to contribute into the same topic, or to change something, let him to ask Wiki Editor staff.

Jonas Larsson September 13, 2005 17:29

Re: CFD-Wiki may be edited, altered, or removed by
Yes, that's the whole idea of a Wiki, that everyone can contribute and improve the content. You shouldn't submit anything to the Wiki which you don't want others to work on and improve later. The Wiki is a living set of documents which evolves continiously. Experience has shown that the "Wiki" process and way of collaborating tends to work quite well and produces high-quality documents.

The Wiki has full revision control and it just takes a click to revert changes or deletes made by someone else. There are also several features in the Wiki to track changes, watch and patrol articles, and, if necessary, protect articles, appoint special moderators and block users who sabotage the Wiki.

Jonas Larsson September 13, 2005 17:36

Re: Jonas it's very dangerous
Don't worry, you can delete or change content, but anything you do can be reverted with a single click by someone else.

Other Wiki's have managed to create and let the community edit articles about the history of Jerusalem and it has worked out very well. Hence, I wouldn't worry too much about the possible conflicts and problems we might encounter in a CFD Wiki. Jerusalem is a bit more problematic so to say...

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