Abstract
A new formula describing the flow impedance of a cylindrical tube was derived from a step response of unsteadystate laminar flow. In spite of a simple form of this equation, it can describe the exactly same frequency response of the flow impedance as that obtained from Womersley's solution. This formula also directly gives the equivalent electrical circuit which is the simple parallel connection of series branches consisting of resistance (R) and inductance (L). The equations for detemining these frequency-dependent R and L components were derived and applied to a frequency response analysis of catheter-manometer system. The discrepancy between experimental and theoretical results, found in a conventional model, was greatly reduced by employing these equations.
