CFD Code

[giramonti]

You guys seem to be a very knowledgeable group, so I'm going to pose a question that's been nagging me for a couple of years. Is there CFD code that exists in the public domain that I can use to program a module to analyze my design models? I can use VB or C++ and I can generate sections (offset) lines in MultiSurf or Rhino.

In addition, since I know only the basics about CFD theory, is there a document where I can learn more as applied to sailboats? I have an AIAA paper (2000-4339) called "CFD Design Sutdies for America's Cup 2000", but it is skewed toward SPLASH code, and a I want a broader perspective.

Working several years for Carl Schumacher, I designed an in-house VPP in VisualBasic that linked with the Hydrostatics functions available through Multisurf OLE. It worked quite well, though I'm doubtful about the accuracy of any VPP. The boats we designed were often much faster than their IMS VPP plots, and they were usually a bit slower than the VPP I wrote.

My doubts about VPP's has led me to pursue new avenues of performance prediction. CFD seems the most reasonable progression, where the shape of the hull is considered rather than the major hull parameters, that don't really describe a hull that well. In other words, many different hull shapes can have the same major hull parameters. It's not possible that they will all perform the same.

Thanks

[Gades]

Hi Giramonti,

I haven't used any of the available codes, but I've seen that there are quite a few ones.

The best site I've found aobut CFD is here (http://www.cfd-online.com/) . There are lots of proffesionals posting in there, plus links and so on.

Are you looking for a 2D or a 3D code?

[Steve Hollister]

Hi Giramonti,

See the link site I put together at

http://www.newavesys.com/research.htm

I haven't updated this site in about 6 months, so some of the links might be broken.

See especially the overview paper called:

***Modern Computational Methods for Ships in a Seaway (SNAME Annual Meeting 2001 Preprint) - Robert Beck and Arthur Reed, 48 page overview of the current state of the art for potential flow and RANS codes

... This paper is not just for sailboats, but covers the whole area referred to as CFD for vessels (resistance, free-surface, RANS codes, 6DOF ship motion codes). Bob Beck was my advisor at Michigan and I have been encouraging him to make his nonlinear CFD code available, but, it is always a work in progress and releasing and supporting the code for the general public is not in the cards. (Model sizes can easily exceed 100MB.)

There isn't any public domain CFD code that I know of, unless you want to include old VSAERO or PMark code, which you may not be able to get your hands on anyway. Although I have a master's degree in hydrodynamics, a master's degree in computer engineering and almost 30 years of constant programming, I wouldn't attempt to write a CFD program unless I could spend all of my time working on it. I also would not like to monkey with an existing public domain code unless there were an active support group (like Linux). There are a lot of horror stories about trying to use public domain codes.

The best bet is to support the work by people like Leo Lazauskas:

http://www.maths.adelaide.edu.au/Applied/llazausk/hydro/hydro.htm

Good luck in your search. Let us know if you find anything new and interesting.