Best OSS CFD Package For High School Physics?

RobHart writes "I am teaching a 'physics of flight' unit to grade 11 Physics students. Part of the unit will have the students running tests on several aerofoils in a wind tunnel. I also want to expose them to a Computational Fluid Dynamics package which will allow them to contrast experimental results with those produced by the CFD package. There are a number of open source CFDs available (Windows- or Linux-based are both fine), but I don't have much time to evaluate which are the simplest to use in terms of setting up the mesh, initial conditions, etc. — a very important issue as students do not have much time in this unit." Can anyone offer insight about ease of use for programs in this niche?

Comments

Re:Too Complicated

[blair1q]

That's what they used to say about computers.

But when I was learning to write Fortran in school in 9th grade, grad students were learning to write Fortran at the university across town, and making more mistakes and understanding it less than I was.

I would expect the CFD program that would suit this class is something that takes a simple grid input for the surface, simple initial conditions, then runs the flow and plots streamlines or vectors. No need to get into the theory behind the sim computations, just show how things flow across the surface.

If the kids are bright, they'll be ingrained with a desire to figure out (a) more about fluid flow, or (b) how a computer knows how fluid flows, or (c) both.

'Ease of use' relative

[multimediavt]

I've taught computational fluid dynamics and molecular dynamics workshops to university faculty members and can say this: You need to setup the examples for them to play with BEFORE class. There's really no such thing as an easy to use CFD or MD package, especially when looking at what it takes to setup initial conditions. I would strongly recommend that you do a good deal of the leg work, especially for participants that do not have the mathematical background or a background in fluid dynamics, period. It will only help you in the end.

This link will take you to lists of free and free-to-academics CFD codes, but the free ones are really, really bare bones in a lot of cases when it comes to UI. I would not turn high school students loose on these codes without pre-determined examples.

Re:Try XFOIL... leave CFD for later

[Davorama]

This is the advice you want to follow. Use XFOIL or some other panel method based program to analyze airfoils along side of your wind tunnel stuff.

You can talk about all the things it doesn't do well (boundary layer separation, transonic flow...) and show them some Color Fancy Drawings made by a more advanced simulation as an aside.

Re:Learning vs Exposure

[Thelasko]

Playing around with flow simulations and seeing how changes in geometry affect flow is fun

Agreed, but I'm afraid that playing with CFD will just leave the students frustrated and convinced that physics doesn't work because they can't get CFD to work. I remember kids in high school, (even some in college) deciding that physics doesn't work because they couldn't get newton's laws of motion to match the results they observed experimentally. In reality, they didn't do their math correctly.

If the author want's to quickly demonstrate the principles of fluid mechanics to his/her students here is my plan:
1) Make sure they have a firm grasp on Newton's laws of motion.
2) Have them drop a paperclip and a coffee filter from the same height and measure how long it takes them to hit the floor.
3) Explain to them that this is the effect of aerodynamic drag.
I performed the same experiment in college physics. It's quick and effective.

Airfoils

[lbarbato]

If you're looking for an airfoil simulator, you might try NASA's FoilSim II. "Elementary," student, and undergraduate versions are available, and the non-applet download gives an even more complete version that allows file output. While it's not a full CFD package, it may be good enough for an introduction to airfoil analysis. And while it's not open source, it is free and in the public domain (since it was government produced).

Also, if you're generally looking for open source physics simulations, you should check out Open Source Physics at http://www.compadre.org/osp/

In particular, a brief search there yielded the Tracker Air Resistance Model - a level appropriate simulation that lets students explore the air resistance of falling coffee cups with both viscous (linear) and drag (quadratic) models.

Nearly all of the OSP items have the source code available for modification of the models.

Re:Learning vs Exposure

[RJFerret]

I believe I saw that demonstration in elementary or middle school back in the 1970s or 1980s. In high school, our physics teacher showed a feather falling in a vacuum (much cooler). Get with the '80s already! ;-)