The hydraulic diameter, <math> D_h <math>, is 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:

<math> D_h = \frac {4A}{U} <math>

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

For a round tube, this checks as:

<math> D_h = \frac{\frac {4 \pi D^2}{4}}{\pi D} = D <math>

External links

• Heat exchanger calculations: Hydraulic Diameter (http://www.livstek.lth.se/People_list/ulfb/b13_heat.htm)