kutta

kutta streams a flow past an airfoil and draws the speed field, the vorticity, smoke streaklines and the lift/drag vectors while you turn the angle of attack. Draw your own shape, cut a wing into wing + flap, animate the control surfaces, and watch the wake fall apart when you push the angle too far.

It is qualitative, not validated CFD. Lattice units stand in for physical ones, so it gets the shape of the flow right — stagnation point, wake, suction over the top, separation as the angle grows — and the actual numbers wrong. Use it for intuition, for teaching, and for a demo that looks good on a projector. Do not size a real wing with it.

Runs right here in your browser. The desktop version (Windows, macOS, Linux) is a single executable with nothing to install, and adds what a browser tab cannot do: opening and saving .afoil scenes, importing SVG shapes, and the native menu.

- Speed, vorticity and pressure views, smoke streaklines, force vectors

- Live lift curve (Cl vs angle of attack) — trace it into stall

- Scene editor: draw closed shapes, split wing + flap, keyframe the control surfaces

- NACA profiles built in; import your own outline from SVG (desktop)

- One executable, no installer, no runtime