GEOGRAPHY & CARTOGRAPHY CALCULATOR
Equationfroude Number
A precise tool.
What is the Equationfroude Number & How does it work?
The Froude number is a dimensionless parameter used in open‑channel hydraulics to compare inertial and gravitational forces acting on a fluid flow.
It is defined as the ratio of the flow velocity to the square‑root of the product of gravitational acceleration and the hydraulic depth, providing insight into flow regimes such as subcritical or supercritical.
Fr = \frac{V}{\sqrt{g D}}
Fr = Froude number
When Fr < 1 the flow is subcritical (wave propagation upstream is possible), whereas Fr > 1 indicates supercritical flow where waves travel downstream only.
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Frequently Asked Questions
What is the Froude number used for?
The Froude number is used to compare inertial and gravitational forces in fluid flow, helping determine if the flow is subcritical or supercritical.
How do I calculate the Froude number?
To calculate the Froude number, divide the flow velocity by the square root of the product of gravitational acceleration and hydraulic depth: Fr = V / √(gD).
What does a subcritical flow indicate?
A subcritical flow (Fr < 1) indicates that wave propagation upstream is possible.
How do I determine if the flow is supercritical?
If the Froude number is greater than 1, the flow is supercritical, meaning waves cannot propagate upstream.
What units should I use for calculating the Froude number?
Use consistent units: velocity in meters per second (m/s), gravitational acceleration as standard 9.81 m/s², and hydraulic depth in meters (m).
Can the Froude number be greater than 1?
Yes, when the Froude number is greater than 1, it indicates a supercritical flow where waves cannot propagate upstream.
What factors affect the hydraulic depth in a channel?
Hydraulic depth is affected by factors such as channel geometry, water level, and flow rate. It is typically calculated as the cross-sectional area of flow divided by the wetted perimeter.
Results are for informational purposes only and do not constitute professional advice.