Who uses CFD?

[MetalAndy]

Hey,

What CFD program does everyone here use, or what do you think is the best? I know my school has Fluent on their computers and I don't know what else. Im looking for one to put on my personal computer maybe, but I haven't decided yet. Thanks for any help, since i'm semi-clueless about these thing as of yet.

Edit: Punctuation

[Eric K]

Fluent is supposed to be one of the best out there if not the best. From what I hear it's a bit hard to set up and run.

We've used Fluent and COSMOSFloWorks

[BeaverGuy]

I would recomend COSMOSFloWorks for someone just starting in CFD and needing to get something done for the car. I started my CFD with FloWorks and later took a class that used StarCD. FloWorks can give you good looking results in a reasonable amount of time with minimal setup. However, you don't have access to a lot of the nitty gritty details and a fair amount of control is hidden from you. This is especially true if you are using the standard version of FloWorks and not the Professional version but for most analyses this isn't a problem. At any rate I strongly recomend taking a class in CFD at some point, and if you can't, deffinitely pick up a text on it and maybe take an FEA class. The help files for FloWorks are good but taking a class gives you a definitively different persepctive.

[Mike Claffey]

Andy it really is a case of horses for courses. Cosmos is great for beginners but I don't recommend it for any detailed work because you will run into its limitations really quick. Its greatest asset, and biggest downfall is its ease of use. ie meshing is easy, but you have no real power over your mesh, stuff like that. I think your time would be best spent learning fluent.

If you want a high level of accuracy in your results your probably going to have to get your hands dirty with meshing and possibly even writing some custom stuff for your problem. So if your in for the long haul go and learn star-cd, but if you want to do a weekends work learn cosmos.

Aero stuff: Fluent, star-cd
Engine stuff: wave, vectis, GT power, star-cd
Flow in a straight pipe: maybe comsos

Regards,

Mike

[golfer17]

ive used fluent before with gambit as a preprocessor and i really liked the way both softwares were setup. i think our school uses star-cd, but i havent had a chance to play with it yet. i would reccomend getting to know whatever cfd software you have available first before you go looking at getting something on your own pc. once you have a better idea of how cfd works and how to use it, then you will be able to better know what software will better suite what you want to do with it.

[Kenny T Cornett]

From my personal experience and training, I too say stick with fluent. There isn't much out there better. As for FSAE, you may be better off with Cosmos just because of time constraints (not enough time to learn somethign else), but definitely look into a stronger package.

I have used Ansys with good success, but as with Ansys on any type of analysis you get lost in the details before you ever get any results.



I'm curious t know if you all are CFDing solid models or surface models... and if surface what you model them in. I ask because I've been working with our aero and asthetics team heavily on Alias StudioTools to do surface only modeling and have generated some fantastic results thus far in terms of goofing off and learning the software. What modeling type do you all use for CFD simulations?

[andyman61]

We're using Fluent for CFD and Gambit for meshing. Fluent is pretty straight foward, I thought Gambit was by far the harder program of the two to get used to.

[Parker]

you guys should feel lucky that your school offers any CFD courses. I had to teach myself FLOworks, which wasnt too hard, but trying to use ANSYS for flow analysis was waaayyy too confusing.

[BeaverGuy]

The CFD course I took was its first time a CFD course was offered below the 2nd year of a graduate program, it was still a graduate course but was open to undergrads. I too taught myself FLoWorks and there was some CFD with ANSYS taught in the FEA class sequence which I didn't take. My partner on the engine team was in the class and I saw some of the stuff that was capable in ANSYS and how the boundary conditions were set up and really didn't like the program. Also, ANSYS uses a Finite Element method as opposed to a Finite Volume method. Finite Element methods are globably conservative while not following conservation laws locally. This can cause results where it looks correct overall but the details of the flow are wrong. Finite Volume methods like those used by Fluent, StarCD, FloWorks and most other commercial CFD packages solve the conservation equations exactly at the node level and will generally give a better result than a finite element method.

[Rear]

For those schools using Gambit/Fluent, do you have site licenses or are you having a research group help you? We have several groups at our school who use the code, but don't necessarily want to help undergrads with access. The school itself doesn't have any CFD campus licenses. Does anybody have sponsorship from Fluent directly?

[GSpeedR]

Gambit is kind of a bastard to use but you can basically use it to import your IGES, mesh it with TGrid, and get the felch out of there. Gambit also reminds me of comic books which is another reason to dislike the program.

I never did aero flow with Fluent (only damper flow) but it is probably adequate for FSAE purposes. You have to write your own code if you want better accuracy. Take a course on CFD if possible, or contact a CFD company and tell them you are a student and want a learning seminar. You can teach yourself any program but when you're doing aero stuff you better have a good idea of how a program properly handles things like boundary layer effects and the like or your results will be nonstellar. You can make pretty pictures in MS Paint.

[Bryan Hagenauer]

Originally posted by Rear:
Does anybody have sponsorship from Fluent directly?

A year or two ago I was able to obtain 2 licenses directly from Fluent for about $100 by emailing the university program and saying pretty please.

[Jersey Tom]

We do minimal amounts of CFD. People have tried using it in the past (FloWorks), but their analysis has been worthless. For example, doing steady state flow analysis of an intake manifold with all cylinders drawing the same vacuum at the same time.

Going to be using it a bit for some simple ducting flow analysis to our radiator.

There's no CFD courses here that I'm aware of (correction, there is one, Grad level, in the Aero dept). We might have Fluent somewhere on campus, but for the most part its FloWorks. Not bad I guess, the interface is definately the worst of the Cosmos apps.

[CrazyDave]

With all this talk about using Solidworks, Star-CCM+ has a interfacing tool with Soidworks. They too sponsor FSAE teams, i believe it was 100 for 10 licenses or something along those lines.

[golfer17]

it seems a lot of people are saying gambit is a bit confusing, but one thing i really liked about it was the ease of changing the geometry by accessing the .jou file. you can easily go in and change all kinds of points and such around by modifying the code and it was extremely easy to figure out. the program would then redo everything with your modified geometry which made it pretty simple to test slightly different geometries back to back if it isnt too complex.

[Pedrot16]

i´m using CFX, it´s very good indeed