Fluids & Combustion (real CFD)
Rising Smoke Plume
∂u/∂t + (u·∇)u = −∇p + ν∇²u (Navier–Stokes)

A buoyant smoke column integrated by the library's Jos-Stam Stable-Fluids Navier–Stokes solver — hot smoke rises and curls into vortices.
Computed & rendered in pure C# on the frozen OnlyCSharp 1.8 library — animation baked to GIF with the library's own
Gif encoder (no GPU, no ffmpeg, no external packages).