Hello, I am trying to get to grips with the Purchase of a CFD package. I have been looking at Fluent, CFX, Star & Cfdesign. Does anyone have opinions on which are the most user friendly or most valuable a tool. I am interested in a huge range of problems (typically gas), low to high Re, Laminar, Turbulent, Multi-phase. You name it we probably need it. Can anyone shed some light?

Hi, I advice you first decide on which method is suitable for your applications then choose a commercial code. Different commercial codes might have the same model. Finish your literature survey (go to library first)then look for your suitable model in any commercial CFD software.

Here is an example read MULTI-PHASE-FLOW SIMULATION in PHOENICS http://www.cham.co.uk/phoenics/d_pol...c/multphfl.htm It explains 4 models.

Best regards Nuray

This question is asked pretty frequently, with a variety of unique circumstances. The answers always include at least one post (my turn?) suggesting that you look at the forums here that pc-online sponsors for each vendor. Then you might like to search the archives for past responses to questions similar to yours.

This is very likely the easiest way for you to build a bit of background. Then you can begin to ask the hard questions!

It would appear that you are interesting in solving a wide variety of problems that will require a wide variety of models (turbulence,radiation, combustion, multiphase,etc.). Therefore, you should find out which of these packages offers all the variety you require. I know that some of these packages have only recently added features such as Eulerian-Eulerian multiphase flows, for example. Others, on the other hand, have had it for years. So, do your homework.

Indeed, this is a common question and somewhat difficult question to give a simple answer. Although everyone here has given good advice, I think you will find that perhaps most (at least the high end codes-fluent, star, cfx etc) of the codes available can handle majority of your needs from the analysis side. Possible exception would be multiphase and combustion? So this is the first place to start, can XYZ handle my list of applications? So now your list is getting smaller. Then, what CAD package (if any) do you use? How do those on my small list handle my geometry? Believe it or not this is probably as important as the application question. Then possibly ease of use. How long with a standard training class and a little ramp up time is sufficient enough before you are producing usable results? my 2-cents...

There is also the question of ease of use vs. available personnel and the trade offs of functionality vs. return on investment. For example, some CFD software products might handle 80% of your needs at a relatively low cost. You could outsource the rest if need be. For example, if multi-phase is really important, that would push you to the higher cost solutions. You mentioned CFDesign so I have to put the plug in that you should also look at EFD.Lab (www.nikafs.com or www.nika.biz). I work for them so you should be aware of that. I'd be happy to have a candid discussion about your needs and the best potential solution (understanding that I'm somewhat biased....but not too forceful!). Email me with you number if you're interested.

When Looking at the packages I see little difference in there capabilities and they would probably deal with the majority of what we require. (Not so sure about Cfdesign though). However at our company (aerospace) we are concerned about the learning curve required to run these packages. (i.e. put rubbish in get rubbish out). Although we mostly look at Fluidy problems there are only a couple of us who now our stuff. For example I'm experimental and theoretical fluids based, so I'm not concerned for myself. I worry about the average engineer who sees this package as a solution and not an aid. He may be too free to use a solution in an aircraft product when he doesn't understand if it correct or not.

Pete,

Given my position I can only suggest you to have also a close look to what NUMECA is offering, which is probably well suited to your needs. Feel free to contact me or my colleague Allan Grosvenor if you are located in the States (allan.grosvenor@numeca-usa.com).

Cheers,

bruno www.numeca.com

Unfortunately I'm based in the UK

No problem, I am located in Belgium...

Bruno

Hi,

If you are in Aerospace/Aeronautical Field think seriously about CFDRC's (www.cfdrc.com) and ACRI's (www.ACRiCFD.com) product, also their is a small company called Cobalt CFD (www.cobaltcfd.com), with some good aeronautical modules. For aerospace application, fluent and starcd are not that good. Newer version of starcd I am not so sure, but older one is not that good. I would personally prefer CFDRC'c product.

Regards

Apurva

Pete, I'd also look into the customer support the different companies offer. This again can be done through CFD online. Support will be esential, especially if you are just starting out. Also look closely into the cost breakdowns. To start with you may just want a single user license, but what of the future, this can include anything from additional licenses for say just model building, to parallel licenses as your system grows, to addtional full user licenses. Always bare in mind that there is a steep learning curve with all the software, and the choice you make now will be hard to change after say a year of using a code (if only based upon the time required to relearn how a new code works). Its a tricky descision for you to make. Good luck Bob

Another suggestion also frequently posted is, Hire an engineer that has CFD experince in your field, (could even make a job post on CFD online where you specify the required fields of experience ) and let that person select the code.

If you are in the UK you have Fluent in Sheffield and CFX in Harwell, Oxon. Both of them are pretty good in what you want to do, Fluent being strong in Lagrangian and CFX having a long experience with Eulerian/Eulerian though its nuclear and CPI background. Both should have fairly large offices and good local support.

Ask them to solve a typical problem for which you have ACCURATE!!! validation data to demonstrate code capability. All the major vendors in the UK will usually do this if there is a definite sale in the pipeline.

CFDRC is not good enough to handle the complicate geometries, you need to use their limited GEOM to create your geometries. The import capability is limited. The meshing is always a problem. CFX is heard of not accurate enough.

However, they have CFD Designer may help.