Calculate the Froude Number.

froude(Q, g, A, DH)

Arguments

Q Flow rate [$$L^3 T^{-1}$$]. Gravitational acceleration [$$L T^{-2}$$]. Flow area [$$L^2$$]. Hydraulic depth [$$L$$].

Value

The Froude Number (dimensionless).

Details

The Froude number is a dimensionless measure of bulk flow characteristics that represents the relative importance of inertial forces and gravitational forces. For open channel flow, the Froude number of open channel flow is defined as $$Fr = \frac{v}{\sqrt{gD_H}}$$ where $$v = \frac{Q}{A}$$ is the flow velocity, $$g$$ is the gravitational acceleration and $$D_H$$ is the hydraulic depth. The Froude number is related to the energy state of the flow and can be used to identify flows as either supercritical ($$Fr < 1$$) or subcritical ($$Fr > 1$$).

Examples

froude(250, 32.2, 171, 1.71) # subcritical flow#> [1] 0.1970234froude(250, 32.2, 57.9, 0.579) # critical flow#> [1] 0.9999867froude(250, 32.2, 45, 0.45) # supercritical flow#> [1] 1.459464