Any free and good CFD software ?

[firasf1dream]

hello guys,
i need please a free and good CFD software to study a design, i am using windows xp and my design will be made by solidworks or catia

[Greg Locock]

http://www.openfoam.com/

linux only so far as I'm aware, so you'll need a dual boot.

[machin]

I've been using Khamsin (http://www.hibouscientificsoftware.com.au/) which is a plug-in for google Sketchup (free), which uses openfoam. It has a 30 day free trial period. I'm using it on Windows 7... not sure about XP. You can import Solidworks models into Sketchup. Took me a few days to get it working, but there's plenty of helpful posts on this forum (search for Khamsin Virtual race car championship).

[Jersey Tom]

I was thinking about downloading some Windows binaries of OpenFOAM just to play around with... but you'd think the best option would really be to just get the source and compile it yourself. I'd have to guess that code optimized to whatever processor you have (e.g. if you can take advantage of AVX, AVX2, or AVX512...) would make a noticeable difference in performance!

[firasf1dream]

I was thinking about downloading some Windows binaries of OpenFOAM just to play around with... but you'd think the best option would really be to just get the source and compile it yourself. I'd have to guess that code optimized to whatever processor you have (e.g. if you can take advantage of AVX, AVX2, or AVX512...) would make a noticeable difference in performance!

i didn;t really get what you mean here and what should i do ?!

[firasf1dream]

I've been using Khamsin (http://www.hibouscientificsoftware.com.au/) which is a plug-in for google Sketchup (free), which uses openfoam. It has a 30 day free trial period. I'm using it on Windows 7... not sure about XP. You can import Solidworks models into Sketchup. Took me a few days to get it working, but there's plenty of helpful posts on this forum (search for Khamsin Virtual race car championship).

does this study aerodynamics around the car ?

but sketch up is more for architecture i guess isn't it ?

[machin]

No, it'll do cars too... here is a video showing some of the cars that have been analysed. It (Khamsin) uses openFOAM, the google Sketchup program is just used as an interface.

[firasf1dream]

waw ! seems awesome thanks a lot
and does it give me all the calculations i need around the car ?

btw does anyone have an idea about FloWizard ? for fluid study, i have it on my laptop i learned a bit how to work with it but the problem i have is when i want to calculate the results, it takes hours and hours and doesn't finish !! so any idea about it ?

[andylaurence]

You're trying to predict the movement of a fluid. It's non-trivial. Expect something simple on a high power cluster to take minutes. Expect a full body simulation of a car on your laptop to take all week.

[machin]

waw ! seems awesome thanks a lot
and does it give me all the calculations i need around the car ?

Yes, it'll give you drag and lift figures, from which you can easily calculate the flow coefficients, if that is what you're after.

I've been doing some analyses of simple vehicle shapes with 0.01m mesh size (on the surface of the car) and it takes about 4 hours to do 500 iterations. That's on a little laptop, so would be shorter on a better machine. I just leave the machine on overnight doing the sums.

[firasf1dream]

aha ok thanks for the info
what about Autodesk Simulation CFD any idea ? because i ordered it
and will it take too long to make the calculations too ?

[Lycoming]

How long it takes to do the calculations depends on how complicated your model is. But generally, only very simple cases will be solved on a typical laptop in minutes.

[firasf1dream]

aha alright thanks

[firasf1dream]

hello guys,
my last choice it will be Autodesk Simulation CFD i bought it and installed it and took a look at it, it's great to work with
2014 version which is the last to work on XP windows, because 2015 no more for xp

as for Autodesk simulation composite design 2015 it will still be working on xp windows

[flyboy2160]

...
I've been doing some analyses of simple vehicle shapes with 0.01m mesh size (on the surface of the car) and it takes about 4 hours to do 500 iterations. That's on a little laptop, so would be shorter on a better machine. I just leave the machine on overnight doing the sums.

The trick to getting viscous CFD to run in reasonable times on personal computers is to have a program that utilizes adaptive meshing. The program will decide how fine the mesh needs to be. I've used this with Nika/ProEFD/Flowsim for years. I sometimes override this for a special need. For instance, when analyzing aero-optical distortion over a sensor window, the optics guy wants a very small uniform mesh over the entire window. But for most everything else, I just set the starting grid to some size to get the calculation running, then let the program add or combine mesh blocks as it sees fit. This saves a huge amount of time over requiring a small mesh where you might not need it.

(I also have an older version ALGOR/Autodesk CFD and have had problems with it - including just getting it to mesh correctly.)

I don't know if any of the free CFD programs use adaptive meshing. The papers outlining the scheme have been in the public domain since ~the late 80s?