Confetti Fall: Chaotic Flutter Dynamics (3D)

Confetti Piece

Piece size 28 mm

Piece mass 40 mg

Air & Launch

Air density 1.20 kg/m³

Launch speed 6.0 m/s

Pieces per burst 18

Live Readouts

Pieces aloft

Mean |ω|

0.0 rad/s

Aero/inertia κ

0.00

Regime

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How it works

Each confetti piece is a thin rigid plate with a full 3D orientation (quaternion) and a full 3D angular velocity ω. The aerodynamic force depends on the angle between the plate's face normal n and its velocity v: force = drag along −v̂ (scaled by how "broadside" the plate is, |n·v̂|) plus a lift-like term along the component of n perpendicular to v̂. The same misalignment also drives a torque n×v̂ that rotates the plate, which changes n, which changes the next instant's force — a real closed feedback loop, not a scripted spin.

cosA = n·v̂,  sinA = |n×v̂|
F = −½ρC_D(A|cosA|)Vv − ½ρC_L·A·V²sinA|cosA|·n̂⊥
τ = −C_T·ρAL·V²·(n×v̂) − C_R·ρAL²·ω·√(V²+(ωL)²)

Because ω is a 3D vector, a piece can precess out of its original falling plane — a genuinely 3D behaviour (side-slip and axis wander) that a single-plane 2D model cannot show. The dimensionless ratio κ = ρL³/m again separates the two regimes: small light pieces (high κ) flutter with rapid, chaotic axis changes; larger or denser pieces (low κ) settle into a steadier end-over-end tumble.

Piece size / mass — chord length and mass of the plate, which set κ.
Air density — scales every aerodynamic force and torque.
Launch speed — initial burst speed from the cannon at the base.
Click the canvas — fires a fresh burst; drag to orbit, scroll to zoom (orbit camera).

Click: fire burst · Drag: orbit · Scroll: zoom

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