Aeroacoustic Wind Tunnel, Aeolian Harp & Mach Sonic Lab

Air Speed Sound Lab — Hear What Sounds Air Makes From 5 km/h to Mach 2.0

Accelerate air from a gentle 10 km/h whisper breeze and singing Aeolian harp wires through a 165 km/h hurricane howl up to a 1,235 km/h (Mach 1.0) sonic boom. Whip your finger across the tunnel to slice the air at measured speeds or play the 12 tuned aero-resonator pipes.

Air Speed: 45 km/h (12.5 m/s) Mach / Regime: Mach 0.04 · Singing Breeze Vortex Pitch: 440 Hz (A4)
Your browser supports HTML5 Canvas to render glowing aerodynamic streamlines, 12 Aeolian resonator pipes, and Mach shockwave cones.
16-Step Aeolian Wind-Organ & Flute Sequencer Swipe fast across the tunnel to whip air · Keys 1–9, 0, -, = play pipes 1–12
Master Air Velocity Throttle & Vortex Resonance

What Sound Does Air Make at Different Speeds? The Science of Aeroacoustics

Air itself is almost silent when moving uniformly, but the moment a moving airstream encounters a taut wire, a pine needle, a hollow bamboo edge, a swinging blade, or the speed of sound itself, kinetic fluid energy converts into acoustic pressure waves. This branch of physics—founded by Sir James Lighthill and Lord Rayleigh—is called aeroacoustics.

Air Speed Sound Lab lets you control wind velocity continuously from `0 km/h` up to `2,470 km/h` (`Mach 2.0`), hear how the frequency spectrum transforms across every speed regime, whip your cursor through the air to hear real-time Doppler blade swishes, and play 12 tuned Aeolian wind-harp resonators.

How to Explore Air Speeds, Sonic Booms & Aeolian Music

  1. Sweep the Air Velocity Throttle (0 to 2,470 km/h): Click ▶ Start Wind Tunnel and slowly drag the Continuous Air Speed Throttle upward—or click the 8 speed chips along the top of the tunnel. Watch the glowing streamlines accelerate and listen as the low-pass filter opens from a soft `12 km/h` whisper into a `45 km/h` singing Aeolian chord, a `165 km/h` hurricane roar, and an explosive **Mach 1.0 Sonic Boom** as you cross `1,235 km/h` (`343 m/s`).
  2. Swipe Rapidly to Whip & Cut the Air: Drag your finger or mouse quickly across the wind tunnel canvas. The engine measures your exact hand velocity in real time, renders a glowing aerodynamic wake trail, sweeps a high-$Q$ shear filter to create a realistic **sword/whip air swish**, and cracks a miniature sonic boom if you whip faster than Mach 1.0.
  3. Play the 12 Tuned Aero-Resonator Pipes: Tap any of the 12 vertical glowing resonator columns inside the tunnel (or press keys 1 2 3 4 5 6 7 8 9 0 - =) to excite flute and Aeolian harp notes powered by the wind stream.
  4. Switch Between 6 Aerodynamic Obstacles: Use the bottom dock to change what the wind is hitting: *12 Aeolian Harp Wires*, *Bamboo Panpipe Jets*, *Mountain Pine Needles*, *Samurai Blade / Whip Shear*, *Deep Canyon Helmholtz Cave*, or *Afterburner Turbine Nozzle*.

Strouhal Vortex Whistling, Mach Cone & Lighthill's 8th-Power Equations

Every frequency shift and shockwave angle in this simulator is governed by three fundamental aeroacoustic laws:

1. Strouhal Vortex Shedding Frequency (Aeolian Harp & Whistling Wires, St ≈ 0.198):
f_vortex(v) = St × (v_air / d_wire) Hz ⇒ Doubling Air Speed Doubles the Musical Pitch!

2. Mach Number & Supersonic Prandtl-Glauert Shockwave Cone Half-Angle (c_sound = 343 m/s = 1,235 km/h):
M = v_air / c_sound, sin(μ_cone) = 1 / M (for Supersonic Flow M ≥ 1.0)

3. Lighthill's 8th-Power Aeroacoustic Jet Noise Law:
I_acoustic ∝ (ρ_air · L²) × (v_air⁸ / c_sound⁵)

Complete Air Speed & Sound Frequency Reference Chart (0 km/h to Mach 2.0)

Air Speed (km/h & m/s) Mach / Beaufort Scale Primary Aeroacoustic Mechanism Dominant Sound & Frequency Band
5 – 15 km/h (1.4 – 4.2 m/s) Mach 0.01 · Beaufort 1–2 Laminar boundary-layer leaf flutter Soft thermal whisper (`180 Hz – 420 Hz`)
35 – 60 km/h (9.7 – 16.7 m/s) Mach 0.04 · Fresh Breeze Periodic Von Kármán vortex street Singing Aeolian harp & pine whistle (`350 Hz – 1,100 Hz`)
85 – 115 km/h (23.6 – 31.9 m/s) Mach 0.08 · Whole Gale High-speed vortex shedding + cavity resonance Piercing rigging howl & canyon moan (`120 Hz + 1.8 kHz`)
150 – 220 km/h (41.7 – 61.1 m/s) Mach 0.15 · Hurricane / Whip Fully developed turbulent shear layer Deep roaring pressure wash & sharp blade swish (`80 Hz – 4.5 kHz`)
300 – 850 km/h (83 – 236 m/s) Mach 0.25 – 0.70 · Subsonic Jet Quadrupole turbulent eddy radiation ($v^8$) High-velocity slipstream & turbine roar
1,235 km/h (343.0 m/s) Mach 1.00 · Speed of Sound Coalesced transonic pressure wall & vapor cone Explosive double N-wave Sonic Boom (`25 Hz – 180 Hz` impulse)
2,470 km/h (686.0 m/s) Mach 2.00 · Supersonic 30° Oblique Mach cone ($\sin \mu = 0.5$) + shock diamonds Supersonic crackle & high-pressure afterburner tear

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Frequently Asked Questions

1. What sound does air make at different speeds?
Moving air produces sound through vortex shedding, boundary-layer turbulence, and shockwaves. Below 15 km/h, laminar airflow creates a soft low-frequency rustle (200–400 Hz). Between 30 and 100 km/h, alternating Von Kármán vortices shedding off wires, branches, and edges generate pitched whistling tones (f = 0.20 × v / d). Above 150 km/h, chaotic turbulence creates a broadband roar, and at 1,235 km/h (343 m/s, Mach 1.0), compressed pressure waves coalesce into an explosive N-wave sonic boom.
2. How does the Strouhal equation determine the musical pitch of whistling wind?
When air flows at velocity v past a cylinder or taut wire of diameter d, alternating swirling vortices detach from each side at the Strouhal frequency f = St × (v / d), where the dimensionless Strouhal number St is approximately 0.198. Doubling the wind speed exactly doubles the whistling frequency (raising the pitch by one full musical octave).
3. What happens in the simulator when air speed crosses 1,235 km/h (Mach 1.0)?
At sea level (20°C), sound travels through air at 343 m/s (1,234.8 km/h). When you push the Air Velocity slider past Mach 1.0—or click the Mach 1.0 Sonic Boom button—pressure disturbances can no longer outrun the flow, forming a conical Mach shockwave with half-angle sin(μ) = 1 / M and triggering a deep low-frequency double N-wave sonic boom.
4. How do I play music with the 12 Aero-Resonator Pipes and Aeolian Strings?
Tap or swipe across the 12 glowing vertical aero-resonator columns inside the wind tunnel (or press keys 1 to 9, 0, -, = on your keyboard). The flowing air excites each resonator at its tuned scale frequency, and raising the master wind speed increases the harmonic richness and whistling overtones.
5. How does the Swipe-Whip Air Cutter work?
Drag your finger or mouse rapidly across the wind tunnel canvas. The engine calculates your exact swipe speed in pixels per millisecond, converts it into equivalent airflow velocity, sweeps a high-Q band-pass filter to create a realistic bamboo/blade air swish, and fires a sharp sonic whip-crack if you swipe at supersonic speed.
6. Why does this wind tunnel visualizer run at 60–120 FPS with zero white blinks?
The studio initializes an opaque hardware-backed canvas ({ alpha: false }), pre-bakes the wind-tunnel turbine cowling onto an offscreen cache, and disables mobile browser tap highlights (-webkit-tap-highlight-color: transparent), guaranteeing zero white flicker.