Hydraulic Diameter of a Right Triangle

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

The hydraulic diameter, abbreviated dh, is used to calculate the Reynolds number, friction factor or for calculating pressure drop across two points.  For most geometries, the hydraulic diameter, or characteristic length, is not equal to the diameter of the shape.  The calculation below is an example of the hydraulic diameter when the shape is a right triangle flowing area.

 $$\large{ d_h = \frac { 2wh } { w + h + \left( w^2 + h^2 \right) ^ \frac{1}{2} } }$$                        Where: $$\large{ d_h }$$ = hydraulic diameter $$\large{ h }$$ = height of tube $$\large{ w }$$ = width of tube