Who here uses OpenFOAM ?
 

I would love to use the program, but I am horrible in math.
What I am looking for is a more visual program.
I can understand programs like Maya or 3DSMax, but it's because they are visual and not so much math is needed to understand the program.

Does anyone know of a CFD program that is more user friendly to non math types ?

I'm bumping this in case someone who may use the program happened to miss it. I'm also contemplating downloading, installing, and learning to use the program and if anyone here has any insight into its usefulness, friendliness, etc. I'd like to hear about it.

It's a free program, so nothing is stopping you. :thumbup:

I have it downloaded, but I'm not smart enough to use it.

Yup, that's the problem all right. The learning curve for such a program is pretty steep and time is an investment as well as money, so I was looking for some input as to whether the program is worth that investment.

I have used versiojn 1.4 with limited success. It has a very very steep learning curve however its flexibility is incredible. You can do just about everything with it if you have the skills. It will do subsonic, supersonic, compressible, incompressible, combustion, and more.

I guess the really big advantage it has is the ease at which you can use multiple computers as a cluster to solve problems.

The best way to learn it is to go through the tutorials and examples until you find an example that is closest to your problem. Its also a good idea to verify your simulation environment against case with an actual experiment like the ahmed bluff body for car aeordynamics simulations.

The thing that has me excited is the EngineFoam application that will allow simulation of engine combustion.

Has anyone used Dolfyn ? It too is free, and looks as if it has an extremely simple interface.http://www.dolfyn.net/dolfyn/files/orka/o01.jpg



When I unzip the file and try and istall the program, I get several 'F90' files.

What is an 'F90' file ? I looked up what an 'F90' file is, and apparently is is for Macs and something called a flotran compiler ( or something like that ).

I'm pretty sure I downloaded the Windows version, but perhaps not ?

F90 files are fortran 90 computer code files

I don't know C++ , or any programming at all.
What I am looking for is a CFD program for dummies.
( No code writing, and extreme algebra )
I'd like to find a program that you just unzip the file, click 'install' on the .exe file, and it does it for you. The next screen that opens when you double click the icon is the welcome screen.

I'd feel like I accomplished something if I could get even that far ( because as of right now I can't even figure out how to install any of these CFD programs. )

:confused: What is a fortran 90 ? Is the fortran 90 a Mac file ?

Fortran 90 is a particular standard of the Fortran language -- it's another computer programming language, like C++ is. Fortran's the great grandaddy of programming languages, and every few years, a new standard is made. It first came out in 1957, and other major standards along the way, including F90.

Where did you find that Dolfyn program, Cd?

----

Back on about your original question -- I'd tried, without too much success, to try and run the windows port of OpenFOAM. Very cryptic error messages, and thus, very little progress made to even try the tutorials on a windows platform. :(

My intent in my spare time over the winter months was to try it out on a spare machine that runs linux. We do lack a "poor man's virtual wind tunnel", and I was hoping to get familiar enough with the workings of OpenFOAM to find a way to make a more user friendly front end for the sort of testing you, I, and others have wanted to run on models of our own cars.

[QUOTE=ChrstphrR;80483]Fortran 90 is a particular standard of the Fortran language

Fortran for Lord Vorgon - ( sounds like some old Sci-fi movie character name )


Where did you find that Dolfyn program, Cd?

Codes -- CFD-Wiki, the free CFD reference

There is also a good one called FeatFlow.


( BTW : My internet / phone line has suddenly developed problems )

I hope I'm able to post this before I lose my connection.

----

I think I'm still on, since I see my last posting.

I have a question for you : If I create a model in a program like Blender, can use it in a CFD program, or does it actually have to be created in a special CFD specific program ?
Everytime that I see an image of a model in a CFD simulation, it just looks like a regular polygon model.

Can help people with OpenFOAM Simulation Needs
 

Hello,

I am a quite capable user of OpenFOAM and I can help people with their simulation needs. You can check out my company, CAEbridge's simulation portfolio on this issue.

Best,

Cem

And the cost ?

The cost can depend on the scope of the project (commercial or personal), the prospect for additional simulation runs and obviously the simulation case complexity. So to keep the answer simpler it can range from "free" with some collaborative mutual benefit to some appropriate amount based on the above variables in other cases.

Cem

I don't know the options yet. Wanted to simulate some kammback/fairing options and was looking at openfoam just yesterday and saying "damn this is tricky"

But the problem of course is much bigger, as first I have to scan my vehicle in (like some diy 3d laser scanner), preferrably with someone in the drivers seat, then can start tweaking the aerodyamics.

But would like to find something visually oriented too.

Well, not to defend my position, CFD is no joke and often requires MS/PhD level knowledge in fluid dynamics, applied mathematics and computer science. If one wants to utilize an open source package like OpenFOAM, "tricky" becomes an understatement as it is not a black box type of application.

Scanning is definitely another issue. I have worked in the automotive industry for 5 years and $ cost is quite steep for a good scanning job. If you are thinking of modding a production vehicle design, I would recommend you to look into 3D Mesh databases online to see if there is a descent reproduction of the external shape. I resorted to this method for a Mazda 6 vehicle for an article I published in a magazine and I was within less than 5% for Cd! May be I was a little bit lucky, but what matters is to prove your concept relative to an initial unmodified design (we call it looking at deltas in the industry). So absolute numbers may not matter that much...

Cem

Cem

Albcem , thanks for your reply. I didn't mean to ignore you. ( Or be rude in any way. )

dcb Have you seen the post on the FREE laser scanning program that was just recently posted at this site ?
( I lost the link DOOOPPP ! I'm looking for it now. )

EDIT : Looks like you are very aware of the 3D scanner ... since you posted it . :)
Thanks a million man !

FYI, there is a Windows version of OpenFOAM on Source Forge since this thread started.
OpenFOAM for MS windows binary release | Get OpenFOAM for MS windows binary release at SourceForge.net

Cheers
KB

Thanks a billion KamperBob !

NP

I'd love to hear a report if you try it.

I just got Puppy Linux running on my laptop. I haven't got OpenFOAM to work yet. So many learning curves. I did get MATLAB running under Linux but had to use software OpenGL. That does not bode well...

Cheers
KB

This linux live CD looks like an easy way to get started without the need for installation: caelinux.com/CMS/index.php?option=com_frontpage&Itemid=1

I haven't tried it myself, but was looking into it.

Well I got the bug and started playing with open foam again. I learned a nice lesson about hard disk space, time, and 3d simulations. You need a lot of space and patience. I ran the pitz daily 3d test case and it used up all 50GB of space I had free on my laptop. It also took 5 minutes to simulate 0.0005 seconds and would have required 100 hours to finish the full half second simulation if I had the disk space to spare.

I have some recommendations for people trying to use it for car simulations. Use linux ( a fast distribution like Gentoo is a good choice ). Have at least 4GB of ram, more is better. Have more than 200GB of free disk space. Compile the package yourself and optimize it for your machine. Compile your kernel yourself and optimize it for your machine.


Some other performance notes. Use a linux kernel that has the transparent hugepage patch applied. A processor with four cores is not that much faster than one with just two cores because they fight over memory bandwidth (Larger level 2 caches help a little). If your going to do a cluster you want a fast network with low latency (gigabit or faster).

An interesting paper on using openfoam for vehicle design

http://web.student.chalmers.se/group...nPaperOFW5.pdf

note that they have access to a super computing cluster

Also noted for that paper, they set their CFD job to run on only 64 or 128 cores of the 8000 the cluster had available. That does make it far more powerful than what most of us have at home, but it's not thousands of times more.

Did your laptop have the same amount of RAM you were recommending, ConnClark? My "spare" machine that's already running Ubuntu's distro of linux has plenty of disk space, but it only has 1Gb of RAM memory, and likely that will be the limiting factor. That, and it's wouldn't be dedicated solely for running OpenFOAM.

Yes my laptop has 4 GB of ram. I once tried to simulate a ramjet without combustion on a dual core desktop with 2GB. It really needed about 8GB of ram for the simulation and started swapping like crazy. At that point every 4k of ram I could free up helped. I even resorted to using some of my video card memory for a fast swap file. It helped some when I off loaded some of the processing load to a single core machine with just 1GB but still it was too slow and I gave up.

You really don't want to swap at all when you simulate so the more ram you have free the better. There is another new kernel feature that uses some of your ram as a compressed swap file that may help as it is less costly to compress and decompress from ram than to swap out to disk but it is still experimental with some quirks.

compcache - Project Hosting on Google Code

I'm still no expert at this but often you can't have enough hardware to throw at serious problems. Another part where you'll need a lot of ram is when it comes time to visualize the data.

I found that there is a basic windtunnel like tutorial case for Openfoam in the tutorials/incompressible/simpleFoam/motorBike directory.

It consumes about 1/2 a Gig of ram when running.

Really glad to see you guys are still trying to figure this out.

+10 :)

How are the OpenFOAM efforts going? I was hoping I could use a simpler program like Khamsin, a Sketchup plugin--but the CFD solver it uses only seems to work with static meshes. I want to see the effect of the dynamic aerodynamic devices in this Chrysler patent: Motor vehicle with flow-influencing ... - Google Patents And only OpenFOAM seems to support dynamic meshes.

I can't figure out any way to simply prototype and test that physically, even with a lifetime supply of Coroplast :/