kutta
A 2D wind tunnel for aeromodelers and anyone who likes watching air misbehave.
Click the tunnel first so it takes the keyboard. Use ↑ ↓ for the angle of attack and V to change the field. The controls are mouse and keyboard only, so on a phone or tablet the tunnel runs but nothing responds to touch yet.
Controls
| Key | Action |
|---|---|
| ↑ ↓ | angle of attack |
| Tab | cycle NACA profile |
| V | speed / vorticity / pressure field |
| S | streamlines |
| G | glow / bloom |
| [ ] | inlet speed |
| Space | pause / resume |
| N | single step, while paused |
| R | reset the flow |
| E | open the editor |
| L | play / pause the animation |
| Esc | back to the foil |
Type a code in the field at the top (2412, 0012,
23012) to pick any NACA 4- or 5-digit foil. Type neko
and you get a cat. It has terrible aerodynamics. That is the point.
What this is
It 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. Underneath is a Lattice-Boltzmann solver, so the wake, the separation and the vortex street come out of the physics rather than being drawn on. Press E and you can draw your own shape, cut a wing into wing plus flap, and animate the control surfaces.
It is qualitative, not validated CFD. Lattice units stand in for physical ones, so it gets the shape of the flow right and the actual numbers wrong. Use it for intuition, not for sizing a real wing.
Files
A browser tab has no file dialog, so the two ends work differently here.
To load a scene, drag an .afoil or .svg
file onto the tunnel. To keep what you built, press
Save and the browser downloads the .afoil
wherever your downloads go. There is no Save As, because the browser picks
the destination.
The desktop version
This page is the whole simulator. The desktop build adds real open and save
dialogs, an SVG import menu, and a native menu bar.
Download it for
macOS, Windows or Linux, or on macOS run
brew install --cask crgimenes/tap/kutta.