Aqueous flow limitation in a tapered-stiffness collapsible tube: upstream transmural pressure does not uniquely determine flow-rate

摘要

In uniform thick-walled tubes conveying an aqueous flow, we have previously shown that large-amplitude oscillation is not necessarily associated with flow-rate limitation. Since tapered-stiffness tubes are a better model of some important mammalian conduits in which flow limitation occurs, such as the pulmonary airways during forced expiration, we have now investigated whether tapered-stiffness tubes behave similarly. A parallel motivation was to find out whether non-unique dependence of flow-limited flow-rate on upstream transmural pressure, as found by Kamm et al.~2 in a tapered-stiffness tube conveying air, occurred.