Suspension Bridge Vortex Resonance (2D)

◆ Vortex-Induced Sway
Wind past the deck sheds vortices at a frequency set by the Strouhal relation f = St·V/D. When that frequency nears the bridge's natural bending frequency, the deck locks into resonance and the sway amplitude spikes — the mechanism behind the 1940 Tacoma Narrows collapse.

Controls

Wind speed 6.0 m/s

Structural damping ζ 0.050

Traffic density 1.0

Auto-sweep wind speed

Wind: 6.0 m/s Vortex freq: 0.40 Hz Natural freq: 0.60 Hz f/f_n: 0.67 Amplitude: 0.00 m STABLE