  In this paper we outline methods for calculating the pressure field inside
flow conduits in the one-dimensional flow models where the pressure is
dependent on the axial coordinate only. The investigation is general with
regard to the tube mechanical properties (rigid or distensible), and with
regard to the cross sectional variation along the tube length (constant or
variable). The investigation is also general with respect to the fluid rheology
as being Newtonian or non-Newtonian.
