Froude Number Calculator

Find the Froude number for open-channel or ship flow.

Velocity

Characteristic length / depth

Gravity (m/s²)

Froude number 0.9578

Formula: Fr = v ÷ √(g·L)

Step-by-step with your numbers:

1. Values used:

2. Velocity = 3

3. Characteristic length / depth = 1

4. Gravity = 9.81 m/s²

6. Froude number = 0.9578

Did we solve your problem today?

The Froude number compares inertial to gravitational forces in a flow.

The math behind it

Fr = v ÷ √(g·L). Fr < 1 is subcritical (tranquil) flow; Fr > 1 is supercritical (rapid).

3 m/s over 1 m depth → Fr ≈ 0.96 (just subcritical).

What is a hydraulic jump?

A sudden transition from supercritical to subcritical flow.