Make the invisible visible. Send smoke past different shapes, change their angle, and explore the wake they leave behind.
Start with a cylinder, then switch to an airfoil. Rotate the shape and watch where the flow separates. Add a second object to explore its wake.
Compare flow patterns qualitatively. Speed and pressure use simulation units; this model does not report calibrated drag or lift coefficients.
Reading the flow
Smoke traces the motion of the fluid. The velocity view reveals slower wakes and faster flow around an obstacle; the pressure view shows relative differences across the tunnel. Keep wind speed and size fixed while comparing shapes, then rotate a plate or airfoil to see how its orientation changes the result.
Inside the model
A GPU fluid solver transports velocity and smoke, then solves for pressure to reduce divergence. Solid cells block flow, the left boundary supplies wind, and the right boundary lets it leave. The approach follows the projection method described in NVIDIA’s GPU Gems.
This is an educational approximation with numerical diffusion and a finite grid. Flow smoothing is a numerical control, not a calibrated air viscosity. Real drag depends on three-dimensional geometry, surface conditions, and Reynolds number. Use these patterns to ask questions, not to predict engineering loads. Airfoil size refers to half its chord; cylinder and square size refer to diameter and side length.
One more perspective
Every toy changes one assumption. Try another and see what moves.
Urban water
Send water through real Japanese neighbourhoods. Change its height and direction, and watch buildings and terrain guide the flow.
Material physics
Shape wet clay with wheel inertia, surface friction, volume conservation, and wall buckling.
