Hazen-Williams Hydraulic Radius

on . Posted in Fluid Dynamics

Hazen-Williams hydraulic radius is a term used in the Hazen-Williams equation for calculating the flow of water in a pipe.  The hydraulic radius is a measure of the effective cross-sectional area available for flow relative to the wetted perimeter of the pipe.  It's worth noting that the Hazen-Williams equation is an empirical formula and, while widely used for its simplicity, it may not provide the same level of accuracy as more complex hydraulic models in certain situations.

 

Hazen-Williams Hydraulic Radius formula

\( r_h  =  (  v \;/\; C \; 1.318  \;  m^{0.54} )^{1 / 0.63}   \)     (Hazen-Williams Hydraulic Radius)

\( v =  C \; 1.318  \; r_h^{0.63}  \; m^{0.54}   \)

\( C =  v \;/\; 1.318 \; r_h^{0.63}  \; m^{0.54} \)

\( m  =  (  v \;/\; C \; 1.318  \;  r_h^{0.63}  )^{1 / 0.54}   \)

Solve for rh

 
flow velocity, v
Hazen-Williams coefficient, C
hydraulic grade line, m

Solve for v

Hazen-Williams coefficient, C
hydraulic radius, rh
hydraulic grade line, m

Solve for C

flow velocity, v
hydraulic radius, rh
hydraulic grade line, m

Solve for m

flow velocity, v
Hazen-Williams coefficient, C
hydraulic radius, rh
Symbol English Metric
\( r_h \) = hydraulic radius \( ft \) \( m \)
\( v \) = mean flow velocity \(ft \;/\; sec\) \(m \;/\; s\)
\( C \) = Hazen-Williams coefficient, see below for values \( dimensionless \)
\( m \) = hydraulic grade line slope \( dimensionless \)

   

P D Logo 1

Tags: Hydraulic Open Channel Hazen-Williams