Hydraulic Radius of a Triangular Channel

Hydraulic radius, abbreviated as \(r_h\), is the area cross-section of water in a pipe or channel divided by the wetting perimeter.  The hydraulic radius (R) of an open channel, including a triangular channel, is a measure of the channel's efficiency in conveying flow.  It is defined as the cross-sectional area of flow divided by the wetted perimeter.

 

Hydraulic Radius of a Triangular Channel formula
\( r_h \;=\; A_c \;/\; P_w  \)     (Hydraulic Radius of a Triangular Channel) \( A_c \;=\; r_h \; P_w   \) \( P_w \;=\; A_c \;/\; r_h  \)
Symbol	English	Metric
\( r_h \) = Hydraulic Radius	\(ft\)	\(m\)
\( A_c \) = Flow Area Cross-section	\(ft^2\)	\(m^2\)
\( P_w \) = Wetting Perimeter	\(ft\)	\(m\)

        

Hydraulic Radius of a Triangular Channel formula
\( r_h \;=\;   z\;h^2 \;/\; 2\;h \; \sqrt{1 + z^2 } \)
Symbol	English	Metric
\( r_h \) = Hydraulic Radius	\(ft\)	\(m\)
\( z \) = Width of Channel Slope	\(ft\)	\(m\)
\( h \) = Fluid Depth	\(ft\)	\(m\)