The Effect of Longitudinal Tension on Flow in Collapsible Tube

Abstract

Simulation experiments in vitro related to flow through a vein and an airway of the lung were performed. The effect of longitudinal tension applied to thin-walled silicone rubber tubes on the relationship between the cross-sectional area of the tube and the transmural pressure, and on static and dynamic characteristic relationships between pressure drop and flowrate through the tube was investigated using five different kinds of specially designed tubes of same size with different applied longitudinal tensions. As a result, the following facts were clarified : By applying longitudinal tension to the tube, it became harder for the tube to be collapsed. Tube movement along the tube axis during the oscillation was restricted and the most largely collapsed portion shifted upstream. The amplitude of the oscillatory pressure drop was much larger than its time-averaged value. The time required for the tube to collapse gradually from a fully open state amounted to 80 to 85% of the period of the oscillation.