Froude Number
Froude Number
The Froude number compares inertia to gravity, classifying open-channel flow as sub- or super-critical and scaling ship resistance.
The Froude number is Fr = v/√(g·L). where v is the velocity, g gravity and L a characteristic length (depth).
Inputs
v := 3 m/s=3 m/s
g := 9.81 m/s^2=9.81 m/s^2
L := 1.5 m=1.5 m
Form the inertia-to-gravity ratio.
Fr := v/sqrt(g·L)=0.78
Results
Below 1 the flow is subcritical (tranquil); above 1 it is supercritical (rapid). A hydraulic jump forms where it crosses 1.
Assumptions & limitations
- Characteristic length is the flow depth.
- Free-surface flow.
- Single-phase liquid.