Scruton number explained

The Scruton number Sc is an important parameter for vortex-induced vibration (excitation) of structures, vibrations caused by rain or wind, dry inclined cable galloping, and wake galloping, the unstable airflow that forms around bridge cables and other cylindrically-structured buildings.^[1] It is named after Christopher "Kit" Scruton, a British industrial dynamics engineer.^{[2] [3]}

It is defined by:^[4]

Sc = (2 \delta _{sm} _{e})/(\rho b ^{2} _{ref}) ,

where

\delta _{s}	is the structural damping expressed by the logarithmic damping decrement,
m _{e}	is the effective mass per unit length,
\rho	is the density of the air, or liquid,
b _{ref}	is the characteristic width of the structure.

Notes and References

1. Web site: MECHANICS OF WIND-INDUCED VIBRATIONS. August 2007. Federal Highway Administration Research and Technology. 17 January 2017.
2. Book: Wenzel, Helmut. Health Monitoring of Bridges. Wiley. 2008. 978-0-470-74018-7. 464.
3. Book: Ted Stathopoulos. Charalambos C. Baniotopoulos. Wind Effects on Buildings and Design of Wind-Sensitive Structures. 31 December 2007. Springer Science & Business Media. 978-3-211-73076-8. 45.
4. Svend O. . Hansen . Vortex-induced vibrations of structures . 2-7 November 2007. 5 March 2021. Structural Engineers World Congress 2007 . Bangalore, India.