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Dynamics & vibration

The chimney that dances

Vortex-induced vibration of a steel stack

Duration
1:06
Year
2026

The case

It wasn't the storm. It was a 29 km/h breeze. For this 40 m stack, 1.6 m in diameter, vortex shedding meets the natural frequency at 7.9 m/s and 0.89 Hz: about 0.34 m of sway at the tip, with no storm. Three helical strakes on the top third break the rhythm, and in the model the amplitude drops by 87 %.

Topics

  • Vortex-induced vibration
  • Resonance
  • Steel stacks

Basis. Generic synthetic case built for this piece. No client data. Not a design verification.

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