Relating The Reynolds Number to the Strouhal Number
Background
Fluid mechanics is overflowing with dimensionless numbers, and one of the most important numbers (if not the most important number) is the Reynolds number. Defined as \(Re=UL/\nu\), it describes the ratio of inertial to viscous forces, essentially telling us if a fluid is laminar or turbulent.
But we cannot neglect other dimensionless numbers. One of the lesser known numbers, the Strouhal number