# froude: Froude Number

Description Usage Arguments Details Value Examples

### Description

Calculate the Froude Number.

### Usage

 1 froude(Q, g, A, DH) 

### Arguments

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

### 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}{√{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).

### Value

The Froude Number (dimensionless).

### Examples

 1 2 3 froude(250, 32.2, 171, 1.71) # subcritical flow froude(250, 32.2, 57.9, 0.579) # critical flow froude(250, 32.2, 45, 0.45) # supercritical flow 

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