REFLECTION COEFFICIENTS IN PULSATILE FLOW-THROUGH CONVERGING JUNCTIONS AND THE PRESSURE DISTRIBUTION IN A SIMPLE LOOP

Analytical expressions for the reflection coefficients in pulsatile fl ow through converging junctions are derived by two independent methods and are used to study the effects of wave reflections on the pressure distribution in a simple vascular loop. A simulated physiological sit uation is used as an example in which the loop is formed by the combin ation of a bypass and a bypassed vessel, the relative diameter of the latter being varied in order to simulate a narrowing. The results demo nstrate how, in the case of a converging junction, the effects of wave reflections on the pressure distribution in one vessel depend on cond itions within the vessel itself as well as in the other. The new refle ction coefficients take into account this interdependence of flow in t he two vessels forming a converging junction, and are shown to be cons istent with reflection coefficients commonly used in diverging junctio ns.