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Kerrin January 30, 2003 00:53

Relative strengths of different CFD packages

I'm trying to get a feel for which CFD package might be best for my needs while not starting off another one of those pointless 'Which is the best CFD package?' type threads. Rather, I though I would try and take a more specific approach to the question.

Q: Out of the big four (I am guessing Fluent, Star-CD, CFX5 and CFD-RC), what would you say are the relative strengths and weaknesses of each be in the following areas:

* General preprocessing/meshing: * Ease of meshing complex geometries: * Convergence speed: * Solver stability: * Postprocessing: * Turbulence modelling: * Combustion: * Range of physical models: * Other:

eg package A might be quite good at meshing but might not be as good as package B when it comes to combustion etc.

That way I (and anyone else reading this), can maybe get an indication of the best package depending on their intended uses for it.

Thanks for your help folks.


Dimitri January 30, 2003 06:37

Re: Relative strengths of different CFD packages
I dont think this that there is an answer to your question. Most of the features you mention are generic and it is obvious that all packages will a have fairly similar overall value. Otherwise, some of them would soon run out of business...

The value of a solution IMHO will come from a mix of the time you will invest in learning the code and the relationship you will succeed in establishing with the support whenever you need it.



Pao January 30, 2003 12:28

Re: Relative strengths of different CFD packages
There are problems in solution accuracy, that also depend on the mesh, turbulent model, execution time.

ed February 12, 2003 20:10

Re: Relative strengths of different CFD packages
Before buying our CFD code we did a quite thorough search of the market, and tested STAR, Fluent and CFD-ACE in detail.

Between STAR and Fluent, I think it depends on what sort of business you're in.

Fluent is great for consultancy work or when you have to do lots of different, one-off models. Its pre/postprocessing is simple and quick, and it has more physical modelling capability than star. Although I'm not sure of the current state of Combustion modelling, my feeling is that Fluent is probably better. Fluent also has both coupled and segregated solvers, which should be a benefit regarding solver stability in certain cases, but I think that STAR will get a coupled solver "soon".

STAR is much harder to get in to, and supplies less physical modelling options built-in than Fluent. But it is very powerful in terms of it's pre/postprocessing Macro language (some people have even written automatic meshing routines in this language!) and it seems to be easier to create User-Defined subroutines which run consistently and converge than with Fluent. STAR is good if you want to model a few types of flow in as efficient and automated a way as possible.

In terms of turbulence modelling, Fluent and CFX have more options than STAR, but STAR is catching up.

The major drawback of CFX that we saw was that it has a structured code (TASCFlow) which has all the physics but not the complex geometry ability, and an unstructured code (CFX 5) which can do complex meshes but not all of the physics. This was last year, so it is sure to have progressed.....

CFD-ACE is a bit like Fluent in terms of point and click ease of use, and is the strongest code out there in terms of radiation, if that's your thing. But it seems to lack flexibility.

In the end we went for STAR, but as you said, it depends what business you're in. As for meshing, that's another story. You can buy meshers as part of the package, or separately, like ICEM.

OK, so I can now expect flak in response from all the code vendors.....

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