CFD Software Options

[gi8u2racing]

What are the best software packages that allow one to do CFD on complete airplanes?

[saadlahori]

u need to have all of these softwares

CFDesign
VisualNastran
ProE
Matlab

These would do full analysis of airplane. They all r linked with each other in order to work on ur design

[gi8u2racing]

I know MATLab, but nothing about the other 3. Are these fairly easy to figure out with an easy to use GUI? ie, Can I be doing sample runs within a day of playing around?

[jetblackaircra]

First of all, there are many many different CFD packages out there. Don't let anyone tell you there is one way to do ANYTHING.

Star-CD www.cdadapco.com
Fluent www.fluent.com
Solidworks COSMOS Flowworks www.solidworks.com

There is even an open source free CFD code called
OpenFoam www.openfoam.org

With all of these you want to have a CAD package that will save in a format that the CFD mesher can use to create a mesh. Usual STL or IGES works.

Make sure you get training in whatever package you use. You can make the CFD say just about anything if you put in the wrong information. It makes a huge difference how you constrain your part and how you setup your boundary conditions. So, make sure you know what you are doing.

By the way, what configuration of aircraft are you analyzing and why do you feel you need CFD? You realize there are much cheaper, simpler tools to use to analyze the flow around an airframe?

[zitron]

Ansys CFX is one of the best CFD software to learn and to use.

But I agree with the above. CFD is not something you can just pick up over the weekend. I studied CFD for 2 years and did my masters thesis on it, I would say I know 20% of what there is to know about CFD!! So before you get CFD, be sure to know what you are getting into, and whether there are other options, like simpler panel method, or wind tunnel testing!

-Z-

[gi8u2racing]

I am only trying to analyze standard configuration 1-3 meter sized aircraft. Now you have me scared away from a full CFD program.

All I want to do is import my SolidWorks files (maybe saved as IGES or whatever), put in some simple flow conditions, and get meaningful feedback. And I need to be able to learn this in like a weekend, or with a book. I can't leave my position to taking formal training offsite right now, we're too busy.

Any help is much appreciated! Thanks

[zitron]

Well, it depends on how much you know about aerodynamics, you know, induced drag, boundary layer, lift distributions, pressure distributions that sort of thing, and what you mean by "meaningful feedback".

I would suggest XFLR 5. You won't be able to import your geometry, but should be able to at least put some bits of wings together that look like it. It's free, easy to use (assuming some understanding of the basics), and since it's based on XFoil, should be pretty accurate.

The is also AVL, which a lot of people use (I never used it) it's also free.

Also, have you tried X-Plane? It's a flight sim that allows you to build your own planes and it computes the performance on the fly. It won't be as accurate, but it's very easy to learn and very flexible (and fun!). I use it for control surface sizing, since being able to simulate how it actually flies is more useful than just knowing roll rate and moment coefficients on a DOS window! Having modelled two of my gliders in X-Plane, I'd say it's pretty good.

I was just looking around, and found this: http://crrcsim.sourceforge.net/wiki/index.php. Not sure how good it is, but hey, it's free!

Cheers,
-Z-

[MIT KID]

I would suggest XFLR 5. You won't be able to import your geometry, but should be able to at least put some bits of wings together that look like it. It's free, easy to use (assuming some understanding of the basics), and since it's based on XFoil, should be pretty accurate.

The is also AVL, which a lot of people use (I never used it) it's also free.


I'd agree that for hobby-level aircraft design, you can't really beat XFLR and AVL, no need to go to a full NS CFD package. Great for generic configuration trades, and getting a first crack at vehicle dynamics. Combine it with Xfoil and a little extra math you and you can get a decent drag build up for most conventional aircraft.

XFLR has a much more straight forward user interface than AVL, but if you read through the AVL users manual and example cases a couple of times you'll realize that it has ALOT of capability for freeware.

http://web.mit.edu/drela/Public/web/avl/
http://web.mit.edu/drela/Public/web/xfoil/

http://xflr5.sourceforge.net/xflr5.htm

-Adam

[jetblackaircra]

Solid advice... However, with the tools you're talking about you should really have someone show you how to use them if you can. Similar to CFD, a panel method code like Xfoil can still give information that is incorrect if you put in the wrong parameters. Keep in mind that XPlane uses a 2D code (actually I believe you have to input the drag polar and Cl Vs Alpha curves for each airfoil) and then approximates the 3D flow field based on your geometry.

You can do this in matlab or Excel yourself with a little know-how.