Step Responses of Liquid Lines With Frequency-Dependent Effects of Viscosity

Abstract

Universal step-response plots are given from theoretical considerations for rigid cylindrical lines containing a compressible Newtonian laminar-flow liquid. The pressure and flow step inputs and pressure and flow outputs for semi-infinite lines can, with the principle of superposition, be used to estimate the responses of a network of lines, terminations, and so on, for any transient input. Where possible, analytic expressions were found for these step responses, but in a certain region of each curve complex numerical routines based on the analytic frequency response were necessary. Analytical expressions are based on propagation and characteristic impedance operators published earlier by one of the authors.