The frequency at which vortex shedding takes place for an infinite cylinder is related to the Strouhal number by the following equation:
Where  is the dimensionless Strouhal number,  is the vortex shedding frequency (s),  is the diameter of the cylinder (m), and  is the flow velocity (m s).
The Strouhal number depends on the Reynolds number , but a value of 0.22 is commonly used. Over four orders of magnitude in Reynolds number, from 100 to 100000, the Strouhal number varies only between 0.18 and 0.22.