Oscillatory Flow Impedance in Electrical Analog of Arterial System:

Abstract

In the analog computer for the human systemic circulatory system, the electrical equivalents of a segment of artery as designed up till now are not satisfactory, because they lack representation of the sleeve effect, which results from the interaction between viscous and inertial forces during pulsatile blood flow. First, a network which accounts for this effect was derived, starting out from entirely different equations. It was surprising to find that this does not alter the circuit completely, but only requires adding to the former circuit a corrective network which, however, may have considerable influence. Second, the effect of the anomalous viscosity of blood was taken into account. Its influence on oscillatory flow has been investigated by Taylor, who derived an expression for the relation between pressure-gradient and flow under the assumption that there exists a small boundary layer of lower viscosity at the wall, and found a similar formula for the case in which the blood is assumed to slip at the wall. The modifications of the electrical circuit, necessary to represent these conditions, are given in this paper and turn out to be remarkably simple.