LETTERS TO THE EDITOR Comments on Flow through Collapsible Tubes at Low Reynolds Numbers
نویسنده
چکیده
In a recent paper by Lyon et al. (Flow through Collapsible Tubes at Low Reynolds Numbers. Circ Res 47: 68-73, 1980), the authors contend that waterfall models adequately predict flow through a Starling resistor only for Reynolds numbers <1. Their basic conclusion was that caution should be used when applying waterfall models to the mammalian circulatory system since Reynolds numbers are usually greater than 1 in most blood vessels. This paper points out what I feel has long been a common misconception: that is, failure to distinguish the basic difference between the waterfall model and the Starling resistor. A Starling resistor is a pressure-regulating system which maintains the pressure proximal to a constriction at a constant value. The maintenance pressure is independent of the flow rate (see panel A of Fig. 1). The only equation describing the Starling resistor model is that Ps equals a constant. This system cannot control flow through the tubing system. When a Starling resistor is connected to a flow source, flow will be determined by the source impedance rather than by the Starling resistor.
منابع مشابه
Flow through collapsible tubes at low Reynolds numbers. Applicability of the waterfall model.
The applicability of the waterfall model was tested using the Starling resistor and different viscosities of fluids to vary the Reynolds number. The waterfall model proved adequate to describe flow in the Starling resistor model only at very low Reynolds numbers (Reynolds number less than 1). Blood flow characterized by such low Reynolds numbers occurs only in the microvasculature. Thus, it is ...
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