In open-channel/fluvial hydraulics, flow state is characterized by dimensionless numbers: the Reynolds number relates inertial to viscous forces (laminar vs turbulent flow), while the Froude number relates inertial to gravitational forces and characterizes the flow's turbulence/energy state as tranquil (subcritical), critical, or rapid (supercritical) relative to the speed of surface gravity waves.
In fluvial geomorphology and hydraulics, the Froude number (Fr = V/√(gD), where V is flow velocity, g is gravity, D is flow depth) is used...
Full option-by-option analysis available to enrolled students.