This page calculates the head loss coefficient and head loss of a fluid in across angled lovers inside a pipe.

The head loss *h*_{L} can be
calculated as:

h_{L} = k_{loss} x (u_{m}^{2} / (2
x g) )

Where *k*_{loss}
is the head loss coefficient, *u _{m}* is the flow velocity in the pipe, and

k_{loss} = +
(1 - 50 / Re) k_{qu}

Where * k*_{qu} is a function of the angle and the
number of louvers based on a table of values (Ref), and *Re*
is the Reynolds Number and is calculated as:

Re = u_{m} x D_{h} / v

Where *v* is the kinematic viscosity of air and *D _{h}*
is the hydraulic diameter of the tube. A tube of square cross section has a
hydraulic diameter equal to the width of the tube.

**References**

Idel'chik, I E. and Fried, Erwin., *Flow Resistance, a
Design Guide for Engineers*, Taylor & Francis, Washington D.C. 1989. p
306.