Scruton number

Template:Short description Template:Use dmy dates Template:Complex 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. It is named after Christopher "Kit" Scruton, a British industrial dynamics engineer.

It is defined by:

$\mathrm{S}\mathrm{c}=\frac{2{\delta }_s{m}_e}{\rho b_{\text{ref}}^2},$

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,
$b_{\text{ref}}$	is the characteristic width of the structure.