Froude Number Rechner — Formel
## Froude Number
The Froude number characterises the ratio of flow inertia to gravitational effects in open-channel flow.
### Formula
**Fr = v / sqrt(g d)**
- *v* = mean flow velocity
- *g* = gravitational acceleration
- *d* = hydraulic depth (cross-section area divided by top width)
Fr < 1: subcritical (tranquil). Fr = 1: critical. Fr > 1: supercritical (rapid).
The Froude number characterises the ratio of flow inertia to gravitational effects in open-channel flow.
### Formula
**Fr = v / sqrt(g d)**
- *v* = mean flow velocity
- *g* = gravitational acceleration
- *d* = hydraulic depth (cross-section area divided by top width)
Fr < 1: subcritical (tranquil). Fr = 1: critical. Fr > 1: supercritical (rapid).
Lösungsbeispiel
River at 3 m/s with 1 m depth.
- Fr = v / sqrt(g d)
- Fr = 3 / sqrt(9.807 * 1)
- Fr = 3 / 3.131
- Fr = 0.958 (subcritical, but nearly critical)