Function for defining the Darcy friction factor using the Reynolds number
. Has different equations for laminar (Reynolds number < 2100) and turbulent (Reynolds number > 2300) flows and also for transitional zone (2100 < Reynolds number < 2300).
function fDarcy extends Modelica.Icons.Function; input SI.ReynoldsNumber N_Re "Reynolds number"; input SI.Diameter D "Pipe diameter"; input SI.Height p_eps "Pipe roughness height"; output Real fD "Darcy friction factor"; end fDarcy;