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Ted Conrad December 5, 2005 04:09

Great Project, one criticism
This Wiki is impressive; congratulations to all. One problem, it seems to me, is that unless one comes to the homepage knowing what the acronym CFD stands for, it is quite difficult to find out. Best, Ted

zxaar December 5, 2005 04:21

Re: Great Project, one criticism
The point is if someone does not know what CFD stands for he probably does not work in Mech engg. It won't hurt if he can not reach this.

Ted Conrad December 5, 2005 18:11

Re: Great Project, one criticism
I'm not sure that your conlusion follows from the premise. The power of a wiki derives from maximizing the number of brains and eyeballs doing useful work on a project, anything that tends to reduce that number is counter-productive. Yes, you want content to be contributed by specialists, mechanical engineers; but important editing work can be done by non-specialists. Indeed, some kinds of editing may best be done by non-specialists. Hence, one design objective of the CFD wiki should be to induce generalists to become involved. Again, great project.

"I consider it the obligation of scientists and intellectuals to ensure that their ideas are made accessible and thus useful to society instead of being mere playthings for specialists." --Bjarne Stroustrup, from "Design and Evolution of C++"

Jonas Larsson December 5, 2005 19:03

Re: Great Project, one criticism
I saw that you already fixed it, good. That is the right Wiki spirit! But I must admit that I'm a bit hesitant if anyone who does not even know what CFD stands would bother to spend time to edit and contribute to a CFD-Wiki.

Michail December 6, 2005 00:55

Re: Great Project, one criticism
to Jonas :

my :)) :)) :))

Ted Conrad December 6, 2005 14:27

Re: Great Project, one criticism
Jonas, I do understand your concern, but let me try to make an analogy to illustrate my point (please keep in mind that I'm not an engineer, mechanical or otherwise, so I may not get this quite right). The CDF wiki is a system designed to produce the best possible CDF resource. Consider all input to the system (writing, editing) as signal. You want to maximize the signal strength while reducing noise. Any increase in signal, such as you get by putting the wiki on the www, increases the potential for noise. Any measures that you take to filter noise carry the risk of reducing signal strength. The beauty of wiki is that the system should filter itself. Becuase you are on the www, you wiil get people visiting the site for reasons you can neither predict nor control. Unless you dramatically restrict write priveleges, you will get noise in the form of spam, defaced pages, bad information etc. But, you will get at least as many visitors who are not malicious and may have something to contribute, if only editing. To the extent that you induce those people to do useful work, you increase your signal and the effectivess of your noise filter.

Ynot December 6, 2005 17:25

Re: Great Project, one criticism
Excellent discussion guys!

I think the topic diverted from the main issue proposed by Ted. I agree with Ted that we need to spread the knowledge. But do you think "Computational Fluid Dynamics" is better than CFD?

The way i am thinking about it is as follows: a guy from the movie industry wants to do a scene where there is some fluid flow etc... Now this designer doesn't know about CFD, and assume the only way to do his scene is through CFD stuff. How will he know about it? Any suggestions?

Now back to the "who edits what" issue

We were discussing a similar subject yesterday regarding wikipedia. Some problems were starting with wikipedia as some poorly researched articles were being placed up there.

However, the CFD-Wiki is slightly less prone to such kind of articles as it is specialized in CFD. Let me just point out two things:

1- A person who is new to CFD (or doesnt know what CFD is), will not dare to edit any article! That person is here to learn about CFD (hopefully). There is always a personal monitor that helps you decide whether you want to edit or not.

2- The beauty of the wiki is its definition. It gives people the space to give and present their expertise in a given area. That's at least what I enjoy when writing an article. It gives me an additional space to share my knowledge.

Now, of course, there are various issues regarding an article, such as the way its written, the notations, the figures etc... all of that stuff contributes to the success or failure of an article, therfore, it won't hurt having people edit some sentences, while some other people will do the equations. a graphic designer might present better figures... and that is for the best of everybody "together we stand, divided we fall".

what do we prefer: Quantity or quality?

Please don't stop the discussion here. i am enjoying it :)

Ted Conrad December 6, 2005 18:39

Re: Great Project, one criticism
I certainly don't suggest you change the take the acronym out of the wiki title, nor that you do a global replace of CFD to "Computational fluid dynamics". Just make sure one doesn't find only the acronym on first arriving at the site.

1. People new to CFD certainly will dare to edit articles; I didn't know what the acronym stood for when I surfed in here two days ago researching wikis (which is why the acronym issue occurred to me,) but I have edited the introduction to the acoustics section for clarity and grammar.

2. Why must you choose between quality or quantity? The "ultimate CFD resource" should have both. You already have quantity and will be getting more, the problem is to control quality.

3. Expertise in CFD does not neccessarily imply expertise in writing good English prose. Further, many contributions here seem to be from non-native English speakers. Hence, there is an enormous amount of editing work to be done.

Michail December 6, 2005 19:32

CFD-Wiki - Great - Here can not be any criticism
Dear Ted

As soon as I'll work in CFD-Wiki team - please correct me and show my mistakes to me (of course if You have enough time to do that).

But I have opinion, that specialists from all over the Earth don't try to keep Good English - the main goal is - the PROGRESS.

And we are making ULTIMATE CFD RESOURSE - it's a GOLD DREAM for any of us.

How we shall do it - it doesn't matter. Just to keep copyrights in order...

I like CFD-Wiki very much for the its community spirit.

Jonas Larsson December 6, 2005 19:40

Re: Great Project, one criticism
Interesting discussion. Of course we want both quantity and quality. In the initial phase of an article or a whole Wiki section quantity is certainly more important than quality. Poor quality is even a good way to get more people to help since they will quickly find misstakes which they can easily correct. Once a section has some quantity quality slowly becomes more and more important though and eventually, as a section grows, quality is more important than quantity.

What worries me most about the development of a Wiki like this is the large work that will sometimes be needed by a single individual (or a group working tightly together and coordinating their edits) to restructure a section and "fill in all the holes" in order to create a fairly complete and objective coverage of a subject. In an "encyclopedia" type of Wiki there is less need to restructure and plan than in this type of CFD-Wiki. Once we have content of good quality we will have to work hard on presenting it in a consistent way with a consistent and complete structure that guides readers in the right directions. This will require a lot of work. It is like planning the chapters, figures, tables and headings in a book and making sure that each chapter has a good introduction, content and ending so that a reader is not lost. There is less risk of getting lost in an encyclopedia since it has a more simple and flat structure.

Ted Conrad December 6, 2005 21:04

Re: Great Project, one criticism
Yes, I think that's right Jonas. Essentially what you have on your hands is a new and quite complex engineering problem. Wikipedia and other wiki's have solved some of the problems already but, as you say, CFD-wiki is a different kind of project and you may need to come up with some novel solutions for a novel wiki.

As is the case with Wikipedia, I suspect that getting content will be relatively easy. However, as you point out, structuring and editing the content is a different matter, and requires an staggering amount of work. Much of this work will be somewhat tedious, and I doubt people will be standing in line for a chance to do it.

Perhaps more explicit editing guidelines would be useful? Perhaps a guide for non-technical editors?

Michail December 6, 2005 21:05

Great Project, NO criticism, let's work
Dear colleagues

I Suppose - as much as we add to the CFD-Wiki - it's better than to have not at all.

So this year we cad add all we only can. Later we shall be able to sort all as only we wish it.

We in Russian have proverb (it concerns this discussion) -

we flow water from empty to emptiness.

Let's calmly work and keep silent. It will be more useful.


P.S. I regret that I changed all pictures in my section and stopped my work. It was something like nervoues breakdown. brrr....

Ted Conrad December 6, 2005 21:45

Re: Great Project, NO criticism, let's work
Michail, I think you are missing something: what we are talking about is work. True it's not the kind of work you do; reseaching and writing on CFD, but it's still work. If work on structure and editing does not go hand in hand with submissions, you are quite likely to end up with a big mess.

I hope you will take this comment in the spirit in which it is intended: As you are Russian and the decision has been made that the wiki will be in English, your work will quite likely require more editing than most. If you give me links to your work, I would be glad to edit it (not, of course, for content).

Again, please understand I am not criticizing you, your work, or this project.

Michail December 6, 2005 21:54

Re: Great Project, NO criticism, let's work
Dear Ted

Here is my work

But I've just began, so there are not a lot to be corrected.


By the way I liked Yours description about signal filtering (i'm familar a bit with it).


Ted Conrad December 6, 2005 22:58

Re: Great Project, NO criticism, let's work
Michail, I made a few small edits, and I'm using your equations to calculate what to have for dinner. -------T

Ynot December 6, 2005 23:04

Re: Great Project, one criticism
What i meant by daring, is not the editing of the grammar and that stuff. A person who doesn't know anything about CFD will not dare rewriting the equations, or the physical description of a turbulence model for example. Even in editing some simple english grammar, there are some technical words would make no sense for a pure writer, but that are widely used by the scientific community.

All of this has been a constructive criticism. The thing that makes me feel releived is the eventual quality control that will prevail, as Jonas proposed.

Finally, I suggest that after the Wiki has been organized and presented in a good manner, a committee should be formed where each member would have the will to monitor the changes in a given section or subject. This committee can be changed every 6 months or so.

Although a fundamental principle of fluid mechanics is the conservation of mass, not everything that flows into CFD-Wiki is allowed to flow out. The way CFD-Wiki is presented will reflect our own image, all of us.

So let's keep up the good work guys.

Michail December 7, 2005 04:24

Re: Great Project, NO criticism, let's work
Dear Ted

Thank You very much for Your help.

Although I don't know, how to use these eqtns to calculate dinner, please feel free to use its. Besides it's not my equations. They have their own authors, but not myself.

Best Wishes


Ted Conrad December 7, 2005 05:35

Re: Great Project, NO criticism, let's work
Dear Michail, It has been an honor. And thank you for modestly reminding me that the equations are not your work; but allow me to remind you that it was your work that brought them together in a project that I do believe will produce the "ultimate CDF resource".

As for how to derive dinner from equations. It involves a paper shredder, the eyes of a toad, and some incantations you probably wouldn't believe in as a scientist. I will spare you the details.

Regards, TC

Michail December 7, 2005 06:10

Re: Great Project, NO criticism, let's work
Dear Ted

Thank You, good joke.

But I feel that I belong to the Russian Church, although I like Dzen and Confucij as well.

Ok, continue our work

Best Wishes


Jonas Larsson December 7, 2005 08:14

Re: Great Project, one criticism
I think that the key to getting this to work is to try to establish a strong CFD-Wiki community with close cooperation between different editors. No one will be able to do these large reviews and re-structuring tasks on his own, but if we as a team work together we should be able to handle it I hope.

I'm not at all sure how this will work out. What scares me is that in a Wiki noone will feel that it is his responsibility to fix anything. From my experience most people, me included, need to have deadlines and need to feel that they are responsible for something and if they don't do this someone will get mad, they will loose something, miss an opportunity or whatever. A Wiki just lives on the good will and spare time of volunteers. But I guess that Wikipedia has already showed that this concept works and most likely is one of the best ways of creating this kind of free and collective references.

About editing guidelines. I have started to write some guidelines on policies, formatting etc. They are linked to from the CFD-Wiki Project section on the main page. I agree that it is important to have this type of guidelines and I hope that we can improve and extend them as the Wiki grows. We just need to make sure that everyone agrees on the things that we put in the guides, otherwise a too restrictive or too-little-discussed guide might scare people away. Noone likes to follow things they don't agree with.

If you want to start a guide for non-technical editors please go ahead. You must be the perfect author - You've already proved us all wrong in our narrow beliefs that non-CFD people would not contribute anything useful to the CFD-Wiki :)

I hope that you enjoyed your soup on toad eyes and convective discretization schemes. Next time try a turbulence model or something. I can recommend the Baldwin-Lomax model. It is quick to prepare and it is also very robust and easy on the stomach. A good thing to eat when you're in a hurry ;-)

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