# Duct pressure drop
# Scope: Darcy-Weisbach duct loss with supplied hydraulic diameter and factor.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

length = 5 m
diameter = 0.2 m
velocity = 5 m/s
density = 1.2 kg/m^3
factor = 0.02

loss := factor*length/diameter*density*velocity^2/2 [Pa]

check duct loss budget: loss <= 20 Pa

scenario alternative: length = 4 m