[Sharlin]

First rule of computer graphics: simple and plausible beats complex and realistic, every time. A noise function you likely have anyway, as noise has a myriad uses in graphics. An FD solver, not so much, at least if you're not working on water/smoke/fire simulations.

[dahart]

I love simple and plausible over complex, but there is a consistent trend over time in CG of adopting the realistic simulation approaches as we tame them. See my sibling comment about curl noise for examples of fake fluid flow, but I have to caveat that writing a simple fluid solver for generative art is pretty easy and a lot less demanding than for simulation or production work. A fluid solver is also, interestingly, less compute than Perlin or simplex noise. Those noise functions are quite expensive to evaluate at a point, compared to the amount of math needed to process fluid for a voxel’s timestep (I’m talking 1-2 orders of magnitude). You can amortize the noise cost if it’s static and you sample it onto a grid, but otherwise, surprisingly, it’s possible for noise to be a more complex and less plausible choice, depending on what the artist wants.