If the cylindrical structure is not mounted rigidly and the frequency of vortex shedding matches the chimneys constructed of thin-walled steel tube can be sufficiently flexible that, in air flow with a speed in the critical range, vortex shedding can drive the chimney into violent oscillations that can damage or destroy the chimney. These chimneys can be protected from this phenomenon by installing a series of fences (sometimes called strakes or spoilers) at the top and running down the exterior of the chimney for approximately 20% of its length. The fences are usually located in a helical pattern. The fences prevent strong vortex shedding with low separation frequencies. The optimal pitch for vortex shedding is a 5D pitch (5 x the diameter of the stack).
Vortex shedding was one of the causes proposed for the failure of the original 
A thrill ride, “VertiGo” at Cedar Point in Sandusky, Ohio suffered vortex shedding during the winter of 2001, causing one of the three towers to collapse. The ride was closed for the winter at the time.
 Governing equation
The frequency at which vortex shedding takes place for a cylinder is related to the Strouhal number by the following equation:
Where is the Strouhal number, is the vortex shedding frequency, is the diameter of the cylinder, and is the flow velocity.
The Strouhal number depends on the body shape and on the Reynolds number.
 Mitigation of vortex shedding effects
 See also
- Aeroelastic Flutter – vibration-induced vortices – by way of contrast
- Vortex induced vibration
- Von Kármán vortex street
- K. Billah and R. Scanlan (1991), Resonance, Tacoma Narrows Bridge Failure, and Undergraduate Physics Textbooks, American Journal of Physics, 59(2), 118–124 (PDF)
- Maureen Byko (May 2002). “Materials Give Roller Coaster Enthusiasts a Reason to Scream”. The Minerals, Metals & Materials Society. http://www.tms.org/pubs/journals/JOM/0205/Byko-0205.html. Retrieved 2009-02-22.
- R. J. Brown. “VIV Lecture”. http://www.mms.gov/tarprojects/485/Session3aVIVApplicationstoDeepwaterPipelines-BrownFile1%20.pdf.
- Failure of the Tacoma Narrows Bridge
- Another explanation of vortex shedding (includes a helpful diagram)
- A movie of the Tacoma Narrows Bridge failure
- Flow visualisation of the vortex shedding mechanism on circular cylinder using hydrogen bubbles illuminated by a laser sheet in a water channel. Courtesy of G.R.S. Assi.