A network element is characterized by a type of fluid section. It has to be
specified on the *FLUID SECTION card unless the
analysis is a pure thermomechanical calculation. For liquids the orifice (only
for 
), restrictor,
branch, and vortex fluid section types of gases can be used by specifying the
parameter LIQUID on the *FLUID SECTION card. In addition, the following
types are available as well (the coefficients for the head
losses are taken from [10], unless specified otherwise):