Hydraulic Radius of a Trapezoidal Channel (Unequal Side Slopes)

on . Posted in Fluid Dynamics

hydraulic radius of a trapezoid US 2Hydraulic radius, abbreviated as \(r_h\), is the area cross-section of water in a pipe or channel divided by the wetting perimeter.

 

Hydraulic Radius of a Trapezoidal Channel (Unequal Side Slopes) formula

\( r_h =   \frac{h}{2} \; ( b + w )  \;/\;  b + h \; ( \sqrt { 1 + z_{1}{^2}  } + \sqrt{ 1 + z_{2}{^2} } \;)   \) 
Symbol English Metric
\( r_h \) = hydraulic radius \(ft\) \(m\)
\( A_c \) = area cross-section of flow \(ft^2\) \(m^2\)
\( b \) = bottom width of fluid \(ft\) \(m\)
\( h \) = depth of fluid \(ft\) \(m\)
\( g \) = gravitational acceleration \(ft\;/\;sec^2\) \(m\;/\;s^2\)
\( w \) = top width of fluid \(ft\) \(m\)
\( P_w \) = wetting perimeter \(ft\) \(m\)
\( z_1 \) = width of channel slope \(ft\) \(m\)
\( z_2 \) = width of channel slope \(ft\) \(m\)

 

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Tags: Hydraulic Open Channel