Chézy formula

In fluid dynamics, the Chézy formula describes the mean flow velocity of steady, turbulent open channel flow:

$v=C\sqrt{R\,i},\,$

where

$v$ is the mean velocity [m/s],
$C$ is the Chézy coefficient [m^½/s],
$R$ is the hydraulic radius (~ water depth) [m], and
$i$ is the bottom slope [m/m].

The formula is named after Antoine de Chézy, the French hydraulics engineer who devised it in 1775.

1 Usage with Manning coefficient
2 See also
3 References
4 External links

Usage with Manning coefficient

This formula can also be used with Manning's Roughness Coefficient, instead of Chézy's coefficient. Manning derived^[1] the following relation to C based upon experiments:

$C=\frac{1}{n}R^{1/6}$

where

$C$ is the Chézy coefficient [m^½/s],
$R$ is the hydraulic radius (~ water depth) [m], and
$n$ is Manning's roughness coefficient.

This relation is empirical.

References

^ Manning, R., "On the flow of Water in Open Channels and Pipes." Transactions Institute of Civil Engineers of Ireland, vol. 20, pp 161-209, Dublin, 1891, Supplement, vol 24, pp. 179-207, 1895

External links

History of the Chézy Formula

Chézy formula

Contents

Usage with Manning coefficient

See also

References

External links