[Ema40]

Hello, I would like to ask some advices.
I use Fluent and now I would like to use Open Foam. Which are the differences?
I think that Open Foam is more difficult, because in totally a Code! There is not graphic interface for the user.
Could you explain to me the practical differences? For example, when creating the mesh, in Ansys I can select the surface to which apply some conditions, but in Open Foam? How to deal with complex domains with difference surfaces and bodies, etc.?

In your opinion, considering that I am not a very expert on informatic (but I can use Fluent for free flow open channels, rotating domains, 3D simulations, ect.), how much time I will employ in learn Open Foam?

Thank you for your suggestions.

[akidess]

If you are an industrial user, you should probably make use of a training course, or be willing to spend a lot of time learing OpenFOAM. If you want, you can use a mesher with a GUI such as Pointwise or ANSA and export a case to OpenFOAM, which might make things easier for you. There are also GUIs for OpenFOAM, such as Engys Helyx, ESi Visual CFD or cloud solutions such as Simscale or Conself.

[Ema40]

Thank you.

I am a student. I know how to use Fluent.
In your opinion how much time, more or less, I will spend in learn from myself Open Foam?
Consider that I know how to use Fluent.

Regards

[JonW]

Hello Ema40

There is one thing you should consider. Commercial CFD softwares like Fluent are really really expansive when you are no longer in the university campus. For one user @ one computer, we would be talking about annual lease price approx 1/3 of the price of an apartment, and you can only lease it on an annual basis. So everything you are learning now about commercial CFD (e.g. fluent) at the university will be likely wasted, when start working at a research institute (or similar outside the campus). Most research institute, small companies etc. cannot afford commercial softwares of the magnitude like the Fluent. Note, I think Fluent is great, but so is OpenFOAM, but the latter is free under the GPL licence, so you can use the latter anywhere, anytime, on any computer, on any number of computers, without restrictions and without paying a cent. If you want to use your life in doing CFD, OpenFOAM is the only answer.

Hope this helps!
J.

[akidess]

Originally Posted by JonW

For one user @ one computer, we would be talking about annual lease price approx 1/3 of the price of an apartment, and you can only lease it on an annual basis.

I don't know where or how you live, but commercial CFD software is significantly more expensive than the lease of my apartment

[JonW]

Ok, some misunderstanding here.
lease = you can only lease the good commercial CFD software’s on an annual bases (not buy)
1/3 of an apartment = as in when you are buying an apartment (not lease it), c.f. the above text: "price of an apartment"

Hope this is clear now
Cheers,...
J.

[Ema40]

Thank you everybody for your help.
I am afraid about the time that I will have to spend in learning Open Foam. Is it so difficult to learn?
Then, Open Foam is a free software. Is it certified? I mean this: can Open Foam be used in the profesional engineering life as a valid software for doing a project? Is it accepted by the Administrative authorities which evaluate your project?

Thank you

[JonW]

OF is as certified as the other commercial softwares. I have seen users of commercial programs presenting results on conferences which is of total nonsense. So using a commercial programs is by no way a guarantee of good results. It all depends on how good CFD scientist you are (how well do you know CFD mathematics like the finite volume?; how well do you know the physics like the continuum mechanics?).

I have heard of bugs that have remained in commercial CFD software’s for years, without anything being done

I have used OF in many projects for the last 4 years, without problems.

In addition to this, since you have access to the source code in OF, you can create a new solver, that solves something special and don’t exists on the marked. This capability is extremely important if you intend to apply for a research grand in CFD (if you are going to work at a research institute after your study, then grands are going to be part of your income for your salary). Now days, most of my OF use, is with my custom made solvers.

Your choice is very simple, if you stick to commercial code, you will most likely not work with CFD after your study,... at all.

[Ema40]

Thank you very much for your support!

And, in your opinion, more or less, how much time do you think that I will need to succeed to simulate by Open Foam the same problems that now I am simulating by Fluent?

Do you know a manual/book/website for people who have never used Open Foam?

Thankyou!

[mqsim]

Originally Posted by Ema40

Thank you very much for your support!

And, in your opinion, more or less, how much time do you think that I will need to succeed to simulate by Open Foam the same problems that now I am simulating by Fluent?

Do you know a manual/book/website for people who have never used Open Foam?

I started to learn OpenFoam one years ago at university. From my experience, you will keep learning how to use OpenFoam for a while, it depends on what you want to simulate. I have been using OpenFoam everyday for 6 weeks for my final placement and I keep learning everyday... So there is no answer to your question.

If you want to learn, there is no particular book. You will have to do the OpenFoam tutorials and figure out how it works.

mqsim

[Ema40]

Thank you.

I deal with turbine, therefore rotating domains, sliding mesh, free surface, complex shapes. Therefore, I am quite afraid.

Thank you

[student666]

Hi,

first of all, you have to fully understand the physic of your problem: std release of OF can helps you, but sometimes you have to modify it, but it requires a deep programming and true knowledge...

my experience (just an opinion) tells me that main problem with openfoam is first of all related to meshing and to obtain a good mesh.

Real problems (industry) has often to deal with so complex shape of the geometry that opensource meshing tools are not so suitable to obtain a good starting mesh; OF cries a lot if you don't feed it with a good mesh...

In any case, saying "I know how to use that specific SW", 99% of times it means that someone is really good to set standard option and press run, and at the end of the simulation, to say." See what wonderful coloured picture I have here?!?"....OF doesn't allow this kind of thinking....

Don't be scared...once you're foaming, you'renot stopping anymore...

Regards

[Ema40]

Thank you very much!
Regards