# Froude Number

A dimensionless number used in the study of fluid flow problems relating the ratio of inertial to buoyancy forces applicable to homogeneous shallow water flow, or two layer flow. Explicitly, in the shallow water approximation the Froude number is:

*where*= Froude Number*F*= characteristic velocity, ms*U*^{-1}= characteristic length scale (fluid depth), m*L*= acceleration due to gravity, ms*g*^{-2}

**See also: **Reynolds Number, Standard Acceleration due to Gravity, Strouhal Number.

**Subjects: ** Mechanical Engineering Physics