I've used the basic idea from that paper to make a surprisingly decent program to create gas-giant planet textures: https://github.com/smcameron/gaseous-giganticus
We liked to call it “curly noise” when we first did it, and I used it on some shots and shared it with other effects animators at DreamWorks at the time. Actually the very first name we used was “curl of noise” because the implementation was literally curl(noise(x)), but curly noise sounded better/cuter. Curly noise is neat because it’s static and analytic, so you can do a fluid-like looking animation sequence with every frame independently. You don’t need to simulate frame 99 in order to render frame 100, you can send all your frames to the farm to render independently. On the other hand, one thing that’s funny about curly noise is that it’s way more expensive to evaluate at a point in space than a voxel grid fluid update step, at least when using Perlin noise which is what I started with. (Curly noise was cheaper than using PDI’s (Nick Foster’s) production fluid solver at the time, but I think the Stam semi-Lagrangian advection thing started making it’s way around and generally changed things soon after that.)
BTW gaseous giganticus looks really neat! I browsed the simplex noise code for a minute and it looks gnarly, maybe more expensive than Perlin even?
In 2014 when I wrote it, 3D Perlin noise was still patent encumbered. Luckily at the same time I was working on it, reddit user KdotJPG posted a Java implementation of his Open Simplex noise algorithm on r/proceduralgeneration (different than Ken Perlin's Simplex noise), and I ported that to C. But yeah, I think Perlin is a little faster to compute. I think the patent expired just last year.
Also Jan Wedekind recently implemented something pretty similar to gaseous-giganticus, except instead of doing it on the CPU like I did, managed to get it onto the GPU, described here: https://www.wedesoft.de/software/2023/03/20/procedural-globa...
it's a painting program where the paint can be moved around with a similar fluid simulation