Open Channel Flow — Manning's Equation

Overview

Open channel flow is the flow of a liquid with a free surface exposed to atmospheric pressure. It occurs in rivers, canals, sewers, and partially filled pipes. The driving force is gravity, not pressure.

Key Formulas

Manning's Equation

$Q = \frac{1}{n} A R_h^{2/3} S^{1/2}$

Standard equation for open channel flow.

Froude Number

$Fr = \frac{v}{\sqrt{g D_h}}$

Determines subcritical vs supercritical flow.

Reference Data

References

• Original Source