Home▸Engineering & Materials▸Suspension Bridge Vortex Resonance (2D)

Suspension Bridge Vortex Resonance (2D)

A driven damped bending oscillator, forced by a Strouhal-law vortex-shedding frequency — raise the wind speed and watch the deck sweep through the resonance lock-in that brought down Tacoma Narrows.

Engineering & Materials2DModerate60 FPS📱 Mobile-adapted⇄ 3D version

This 2D companion strips the 3D scene down to a side-view engineering diagram: wind speed sets a vortex-shedding frequency via the Strouhal relation f = St·V/D, which drives a damped bending oscillator representing the deck's first mode. Raise the wind slider slowly and the amplitude gauge spikes when the shedding frequency locks onto the bridge's natural frequency — the same lock-in mechanism behind the 1940 Tacoma Narrows collapse — then falls back once wind speed carries the forcing frequency past it.

⚙ Under the hood

Semi-implicit Euler integration of a driven damped harmonic oscillator (F = -kx - cv + F0·cos(ωt)), with ω set by the Strouhal vortex-shedding law and traffic load feeding back into the modal mass.

suspension bridgevortex sheddingresonancestructural dynamicsstrouhal number

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install