Froude Number Calculator

Enter value and click on calculate. Result will be displayed.
Select calculator :
 
Flow Velocity (V) :
m/s
Acceleration of Gravity (g) :
m/s2
Mean Depth (hm) :
ft
Result:

What is a Froude Number Calculator?

A Froude Number Calculator computes the Froude number (Fr), a dimensionless quantity used in fluid dynamics to compare inertial forces to gravitational forces in a flow system. It helps determine whether a flow is subcritical, critical, or supercritical.

The formula is:

Where:

  • Fr = Froude number
  • V = Flow velocity (m/s)
  • g = Acceleration due to gravity (9.81 m/s²)
  • L = Characteristic length (e.g., water depth in open channels)

Why is a Froude Number Calculator Important?

  • Helps analyze open-channel flow (rivers, canals, spillways)
  • Determines flow regimes:
    • Fr < 1 (Subcritical Flow): Slow, controlled by gravity
    • Fr = 1 (Critical Flow): Transitional state
    • Fr > 1 (Supercritical Flow): Fast, dominated by inertia
  • Used in ship hydrodynamics to predict wave resistance
  • Assists in aerodynamics and hydraulic engineering

How Does It Work?

  1. Input values for velocity (V) and characteristic length (L).
  2. Use the formula
  3. Interpret the result to determine flow behavior.

Example: If water in a canal flows at 3 m/s with a depth of 0.5 m,

Since Fr > 1, the flow is supercritical (fast and turbulent).

When is a Froude Number Calculator Used?

  • Hydraulic engineering (dam spillways, river analysis)
  • Maritime industry (ship design, wave formation)
  • Aerodynamics (airflow analysis in wind tunnels)
  • Civil engineering (flood control, drainage systems)