# Strouhal number

In

dimensional analysis, the

**Strouhal number** is a quantity describing oscillating flow mechanisms. Often, it is given as

- Sr = f*D/V

where Sr is the Strouhal number, f is the frequency of

vortex shedding, D is the hydraulic diameter of the object in the fluid flow and V is the velocity of the fluid.
The Strouhal number is a function of the

Reynolds number Re and in the region 200

See also: dimensionless number (which includes a listing of other dimensionless numbers)