Acoustic Levitation: The Floating Skull (2D)

Ultrasonic Drive

Drive frequency f 40.0 kHz

Drive amplitude (normalized) 0.60

Cavity length, half-wavelengths n 4

Air damping 0.30

Object radius 3.0 mm

Live Readouts

Wavelength λ

Pressure at skull

Object mass

Trap / weight ratio

Status

How it works

This is the 2D companion to the 3D acoustic-levitation simulator, computed independently rather than a flattened render of the 3D scene: instead of an orbit-camera field of standing-wave rings, it draws a side-view instrument column — the instantaneous pressure field p(y,t) painted as a live red/blue heat-map along the cavity, with the cos(ky) amplitude envelope traced as a curve beside it, and a numeric readout of the exact pressure the skull feels at its current position.

λ = c / f,   k = 2π/λ,   ω = 2πf
p(y,t) = 2·A·cos(k·y)·cos(ω·t)          (heat-map + envelope curve)
F(y) = K·sin(2·k·y),  K ∝ A²·V·k        (restoring force toward nearest node)
m·dv/dt = F(y) − m·g − b·v

Just as in the 3D model, the object is trapped at pressure nodes (marked with dashed green lines) because it is denser and less compressible than the surrounding air — the same physics behind real ultrasonic levitators. Turning drive amplitude down far enough drops the maximum trap force below the object's weight and it falls through the column.

Drag the skull along the column to pull it off its node — release to watch the restoring force and the live pressure readout react in real time.
Drag the background to pan, scroll (or pinch) to zoom — a genuinely 2D-native way to inspect the field close up, which the 3D version's orbit camera doesn't offer in the same way.
The heat-map redraws every frame from the same p(y,t) formula driving the envelope curve, so the color you see at the skull's height is exactly the number in the "Pressure at skull" readout.

Compression (+p) Rarefaction (−p) Pressure node (trap)

Drag skull to displace · drag bg to pan · scroll to zoom

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