Strouhal Number Formula

Equation for calculate strouhal number is,

$S t = \frac{f \cdot L}{U}$

where,

f is the frequency of vortex shedding
L is the characteristic length (for example hydraulic diameter, or the airfoil thickness)
U is the flow velocity
St is the Strouhal number (dimensionless)

f is the frequency of vortex shedding

L is the characteristic length (for example hydraulic diameter, or the airfoil thickness)

U is the flow velocity

St is the Strouhal number (dimensionless)