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Off of quantum mechanics for a moment, and back to the world of macroscopic (newtonian) fluid physics. We’ve been playing a lot with fluid (particle-based) simulations lately, looking at lift, drag, and turbulence, the bernoulli effect, eddies, and other such-like chaotic phenomena.  (“Macroscopic” would be putting it a bit too strongly; Maybe “mesoscopic” is the right word?)

I had in mind actually making a Navier-Stokes game, but it turns out that there are already a bunch of great apps out there that simulate these phenomena perfectly well, and are also very fun! I’ve tried out at least a dozen — I only bother with the free ones! — and two are of special note.

The first is Wind Tunnel (Free), by Algorizk (which I assume is either a name or a pun). This is a simple but extremely nice app with all the right capabilities. You can draw arbitrary shapes, view in particle, smoke, pressure, or speed modes, and calculate overall lift and drag. Here are some examples:


There are a bunch of pre-drawn objects (although not many), and you can draw your own objects. My only complaint about this app is that you can’t rotate solid bodies, like the wing above, in order to experiment with angle-of-attach (that is, the position of the object with respect to the flow).

The other great example of a fluid sim is Powder Game. The free version is ad-supported, but the ads are along the bottom, and not too annoying. In addition to being an newtonian fluid simulator, Powder Game has tons of special types of particles:


This lets you do a ton of very fun experiments, like exploding things and watching the chaotic dynamics on Nitro!


You can spend hours with either of these apps in the perfect paradigm of learning-by-playing.

In another post I’ll talk more about some great newtonian sims that are a truly macroscopic, which is fun (and educational) of a very different sort, at a very different level.