Manning Open-Channel Flow

Compute open-channel flow rate, mean velocity, and Froude number from Manning n and slope.

visual calculatorMultiphase Flow

Read the flow shape before trusting the number.

This page turns a CFD setup into regime, scale, and dominant-effect cues. Adjust the calculator below and compare the moving graphic with the computed result.

input scale

model

check

open channelManningFroudeshallow water

formula

KaTeX rendered

\begin{aligned}\text{Q = (1/n) A R\_h\^{}(2/3) S\^{}(1/2)}\end{aligned}

ASCII source

Q = (1/n) A R_h^(2/3) S^(1/2)

area A (m^2)wetted perimeter P (m)bed slope SManning ntop width B (m)

R_h (m)

0.6250

Q (m^3/s)

1.5411

U (m/s)

0.7705

0.2751

Manning is a quick uniform-flow estimate for rivers, channels, and shallow-water CFD boundary checks.

open channel Manning Froude shallow water