The hydraulic diameter, $D\_h$, is a commonly used term when handling flow in noncircular tubes and channels. Using this term one can calculate many things in the same way as for a round tube.

Definition:

$D\_h\; =\; \backslash frac\; \{4A\}\{U\}$

where A is the cross-sectional area and U is the wetted perimeter of the cross-section.

For a round tube, this checks as:

$D\_h\; =\; \backslash frac\{\backslash frac\; \{4\; \backslash pi\; D^2\}\{4\}\}\{\backslash pi\; D\}\; =\; D$

The Manning formula contains a quantity called the hydraulic radius. Despite what the name may suggest, the hydraulic diameter is not twice the hydraulic radius.

External links

Fluid dynamics

Hydraulischer_Durchmesser | Diametro equivalente