# Hazen-Williams Mean Flow Velocity Equation

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

This fluid velocity formula is used in Hazen-Williams equations and the coefficient formula.

## Hazen-Williams Mean Flow Velocity Equation Formula

$$\large{ v = 1.318 \; C \; r_h^{0.63} \; m^ {0.54} }$$
Symbol English Metric
$$\large{ v }$$ = mean flow velocity $$\large{\frac{ft}{sec}}$$ $$\large{\frac{m}{s}}$$
$$\large{ C }$$ = Hazen-Williams coefficient $$\large{dimensionless}$$
$$\large{ m }$$ = hydraulic grade line slope $$\large{ft}$$  $$\large{m}$$
$$\large{ r_h }$$ = hydraulic radius $$\large{in}$$ $$\large{mm}$$