# Hydraulic Radius of a Triangular Channel

on . Posted in Fluid Dynamics

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 $$ft$$ $$m$$
$$A_c$$ = area cross-section of flow $$ft^2$$ $$m^2$$
$$P_w$$ = 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 $$ft$$ $$m$$
$$h$$ = depth of fluid $$ft$$ $$m$$