Urban wind, turbulence included
An unsteady 3D solver over a city (Stam stable-fluids plus a Smagorinsky LES eddy viscosity). Each frame: semi-Lagrangian advection → turbulent diffusion νt = (Cs·Δ)²|S| → pressure projection ∇²φ = ∇·u by red-black SOR, no-flow on buildings. Momentum advection produces real wakes, recirculation and vortex shedding behind the towers. It has to run live, because turbulence is unsteady. 70k tracers, coloured by speed.
WebGPU not available in this browser
The LES solver needs a WebGPU-capable browser (Chrome/Edge 113+, or Safari 18+).
The WGSL source ships in the bundle either way, so open src/wind.ts to read it.
Plate 06 · unsteady 3D Navier–Stokes · WGSL Drag to orbit · scroll to zoom · procedural city · stepped live on the GPU
Happy to walk through any of it.
Also built: embedded systems, moving-map engines, production Rust against Norwegian national geodata, and a live product of my own at solrapport.no.
bjreppen@gmail.com