[ArtyB]

Hi All,

I'm interested in designing an aerodynamic human-powered vehicle. I've been trying to find a free open source cfd program to do that with. I use Linux, but Windows would be OK too if necessary. I'm finding it hard to find codes with turbulence models, and with enough documentation/examples to work out how to calculate drag values from simulations. I know getting physically realistic values might be tough, and also that the computational time might be great to achieve precision. However trends/ approximate values would be useful. I do have a background in physics too.

I've tried Elmer, seems reasonably well documented and cross-platform, fairly easy to use, but I'm not getting convergence on the simulations I'm trying.
I've looked at OpenFlower, looks interesting, but hasn't been updated very recently. FreeCFD and Gerris seem to lack turbulence models at present? FreeCFD very new, looks promising though.
OpenFOAM looks as though it might be the best for precision, but seems a beast to install, and I haven't found any tutorials/examples of that type of calculation. FreeFOAM /OpenFOAM-mswin look interesting and have looked at Symscape/BlueCFD also look interesting, but not fully ready for use yet...

So, to Code_Saturne... It is a validated code, and thanks to the guys at Manchester Uni in the UK who provide a binary distribution (including Salome) installation was easy, and I've followed their unseful tutorials. Code input files are in French though, and haven't found much documentation...

So, to questions:

What codes/tutorials would others recommend?
What turbulence models? Re~1E6, air.
Do any of you have examples of (ideally moving road), wind tunnel type calculations?
Examples of how to extract drag forces and hence coefficients?

I'd have thought that calculation drag values would be quite common application, and have been surprised how little I've found on the web...

Thanks in advance,

A

[gocarts]

For a Caedium (formerly SymLab) RANS Flow tutorial on a rotating wheel with moving ground that includes a drag calculation try:
http://www.symscape.com/node/831

Caedium RANS Flow isn't free, but it's modestly priced (with free 30-day trials), runs under Windows and Linux with a GUI, and uses a custom version of OpenFOAM.

Full disclosure: I represent Symscape the developer of Caedium. OpenFOAM is a trademark of OpenCFD and is unaffiliated with Symscape.