[linnemann]

Hi all

I see the discussion is being taken onto a parallel branch of its own.

I just wanted to put in my two cents. I have experience with a couple of commercial codes and have even been on some training session in them.

Specifically I had switched to a new company which employed another CFD code than I was used to. So onto an introductory course for good measures. To my surprise the introductory course was about pointing an clicking held by people clearly not able to answer all my deeper question to the code.

At the same course were a couple of other people from the industry and they had no prior knowledge to CFD and the numeric behind it.

So I asked them (teachers) why they held a course on how to use the program before they (attendees) even knew what CFD was. The answer surprised med a lot since they stated that "people would be scared of CFD if they had to know the theory behind it". Ok so they want to sell licenses, well that's fair enough.

In my eyes this equals giving an infant a loaded gun with the safety turned off. If people blindly trust the results and pretty colors, without knowing the limitations of eg. a k-e model, upwind scheme, they could be designing structures/devices that could be potential time bombs.

I know most company's have validation steps an so on to prevent this, but still. This again comes down to "what should a CFD engineer know" and that's a though question to answer. I would say more than most of the people here in the forum, when they put "help me im a noob" as a thread title.

In my opinion I feel the commercial codes are producing fair results, but often they are closing and open doors (doors I do not want to open/close) in order to create stable (residual) results.

So If you want complete control use OpenFOAM because what you read in the theory, that might crash a case, will happen in OpenFOAM. You might see this as a downside, but for me it is a way of constantly make sure i use the right mesh/schemes/solver to produce the most correct results.

For example I know some of the codes have started to include features that disables solving on problematic cells. I, for one, do not want this (I can disable it I know).

So instead of going the commercial way I have introduced/implemented OpenFOAM for the problems we have. Cases which like Audi, VW are much alike.

So I have to agree with Eugene when he says that OpenFOAM scales (in number of cases run) better than commercial because you are not limited by licenses. Do not think that OpenFOAM necessarily is free, if you want you can by support contracts which are often cheaper than a single commercial license. We have such a contract and it has helped us a couple of times, but mostly in the implementation phase.

If you do many different cases such as combustion on day, free surface the next, multiphase flow the third. I would recommend going commercial since the setup time will be faster.

Although if you like me have a couple of years experience using OpenFOAM it wont take you that long to setup for a different physical problem.

Ok so you are missing a feature/solver well go out an get one of the many consulting companies which specialize in OpenFOAM to do the implementation for you, or do it yourself.
We have done this (first approach) and it was much cheaper/faster than having one of the commercial companies do it (which by the way also didn't have the feature).

You might now think "What a fanboy", well you might be correct, but you might find yourselves in the same position in a couple of years time if you happen to go through something similar as me.

I believe that people doing CFD should know the theory behind it. That no "right" CFD package exists, only one that fit your needs. So the discussion is really not on commercial vs open source. It is in how you implement and use it and if it fits your specific needs.

No CFD code is free, in my opinion, you just switch the expenses from licenses to support/features. The price tag will be different and the number of cases you can run simultaneously. In the end you will end up with a result which is what you wanted in the first place, open or not. And it is up to you to validate the accuracy of this result, you are in control.

I will although say that if one has only tried commercial or OpenFOAM you owe it to ourselves to try the other (if you have access to both). This way you will have the possibility to make your own evaluation without anyone influencing you.

I have no problems with biased input (and neither should you) because it just shows that the code does what they need and that they are satisfied with the results. It is up to you to filter the input much like you do in literature studies.

Probably my longest answer to anything yet

[holger_marschall]

Hi,

why has the last post been deleted?

best regards,

[mbeaudoin]

Hello Holger,

I did also received a prior message from this thread this morning.

The message was posted by chrisadam12, but it looks to be a dupe from a message previously posted by Andy_ on April 19, 2010, 05:10.

Maybe this is a glitch from the Forum software.

Best,

Martin

Originally Posted by holger_marschall

Hi,

why has the last post been deleted?

best regards,

[alberto]

Same here. Searching by nick, that user does not seem to exist though.

Best,

[akidess]

I (and possibly other people) flagged that message as spam. It was a copy of post nr. 2 on this thread by a new user, and all that was added was a signature with a link about search engine optimization.

- Anton

[alberto]

Thanks.

[nileshjrane]

@linnemann

Well said.. i agree with you..everyone should try both ways and then decide for the better for their own good. I have used commercial softwares, research codes and now openFoam. Personally i find that every thing was good at its own place. Everything is better for something. Otherwise it wouldn't have existed at first place.

I see people who have no academic CFD background playing CFD engg in industry after doing some 6 month diploma course in some commercial software. (I have had this same experience of seeing naive people in so called "advance user training" of a leading commercial software..).

On the other hand, open source softwares lack user-friendliness, at least in the initial part of their use. I am really struggling to get going with open source things. Its really an uphill task to figure out how to use a tool in the best way possible without proper documentation or help. But i also find it a challenging and interesting task to learn all these things. If you have time and interest then there's nothing like it. (today only i finished making a mesh using blockmesh in 3 days (my 1st mesh in blockmesh), same mesh i can make within an hour or two in a commercial meshing package, but then it would have never felt so good that way... All personal preferences..)

There is no single accurate route in CFD, no universal thumb rules. So no one code/software can be better than other in every respect. Each one gonna have some pros n some cons. Anyway, the one which is not good enough will perish eventually. So why don't we let the time decide which thing is better?? Till then we should only decide what is better for us rather that what is best for everyone.

Personally i think that knowledge should be free...exploring new things is the ultimate human quest..i think it better be done together..openly and freely..

[marupio]

What many people don't realize is OpenFOAM is "paid software"... it is commercially funded. There are two independent companies who fund its development through their consulting and training activities. There is a world of difference between commercially funded opensource software, and volunteer-based opensource software.

[alberto]

Originally Posted by marupio

What many people don't realize is OpenFOAM is "paid software"... it is commercially funded. There are two independent companies who fund its development through their consulting and training activities. There is a world of difference between commercially funded opensource software, and volunteer-based opensource software.

As many successful open source projects... Being commercially funded has not positive or negative implication per se. For example, I think that up to now it had more positive than negative implications for what concerns OpenFOAM, since it ensured the project keeps going on and it is well maintained. Of course there are project that do the same only with volunteers, but it is often much more difficult.