# Hydraulic Diameter

on . Posted in Fluid Dynamics

Hydraulic diameter, abbreviated as $$d_h$$, is normally used when the flow is in non-circular pipe or tubes and channels.  Circular pipe has the same pressure drop of a rectangular channel but a greater average velocity.  Square or rectangular pipes have a greater weight and a greater pressure drop compared with a circular pipe with the same section.  For established shapes, various calculations are linked below.

## hydraulic diameter formula

$$\large{ d_h = \frac { 4 \; A_c } { P } }$$
Units English Metric
$$\large{ d_h }$$ = hydraulic diameter $$\large{ ft }$$ $$\large{ m }$$
$$\large{ A_c }$$ = area cross-section of flow $$\large{ ft^2 }$$ $$\large{ m^2 }$$
$$\large{ P }$$ = wetting perimeter cross-section $$\large{ ft }$$ $$\large{ m }$$

## Hydraulic Diameters for Specific Flow Profiles

Tags: Hydraulic Equations