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DeMan February 25, 2010 10:26

Commercial or OpenSource
Hi All, I have a question for the experts.
We are about to begin some modelling and no-one in the company really knows what they are doing. We need to outsource. I need to know if we should be going with OpenFOAM or a commercial product. Main application is industrial, where high air speeds, turbulence, compressible flows and rotating machinery all play a role. Also thermodynamics in some experiments.

So Q's as follows:
1) Is OpenFoam capable of this type of work, or should we go with a commercial product? I am told CFX may be the way to go.
2) Are there any consultants availablein Australia/NZ who can offer contractual services using OpenFoam
3) How does SolidWorks Flow Simulation stack up? I feel our Engineering contractor (who does not believe in CFD) will try to get the work based on their integraction with existing CAD material. [Its my poor assumption that solidworks may not compare to the likes of Fluent/CFX/OpenFoam]

Appreciate your honest feedback!


Vladik February 25, 2010 14:52

An answer to the first question is perhaps as follows:

1) If you plan to simulate unsteady flows, then OpenFOAM can do the job, but the timestep will be 10 to 50 times smaller than that in CDX because of limitation of the Courant number, which must not exceed 1. Correspondingly, getting results with OpenFOAM is going to be too slow and boring.

NewtonKF February 25, 2010 15:47


I think both opensource and commercial software can do the simulations you need.. The great difference is the way you learn and use them... Remember that the best software is the one that you know how to use...

Commercial softwares are, usually, easier to use and learn than opensource for numerical simulations... CFX and fluent are good and easy softwares to use for consultant simulations... OpenFoam, is best for academics... but more people are migrating to open-software to reduce cost of operation... If you think in complex simulations, you probably will need some package that can run in parallel, so its cost is higher...

And about the CFL number cited by Vladik, you will have to use this advective time increment criterium in any software that run explicit or semi-implicit simulations... Although CFX may allow you to use CFL numbers greater than one, for realistic simulations, you will generally need to use CFL smaller than 1, independently of the software you will use...

good luck...

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