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The pressure-flow method: some fundamental concepts.

C C Yates·B J McWilliams·L D Vallino
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Abstract

The pressure-flow method introduced by Warren and DuBois is a useful method for estimating velopharyngeal orifice area. However, this investigation shows that unless geometric similarity of subject and model exists, the value of the flow coefficient k used in the equation to estimate velopharyngeal orifice area cannot be established from model tests. Use of k = 0.65 is questioned as that value is typical of thin plate orifices, a geometry that is not a good representation of the velopharyngeal passage. Values of k from the literature and from steady state tests using a model similar to Warren's are presented to show the effect of various inlet shapes. The influence of inlet shape supports the conclusion that k may be significantly higher than 0.65, conceivably approaching values in the range of 0.9 to 0.97, depending on the orifice geometry.

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HumansModels, BiologicalPalate, SoftPharynxPressurePulmonary VentilationRheologyJournal Article

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C C Yates, B J McWilliams, L D Vallino. 1990. The pressure-flow method: some fundamental concepts.. https://doi.org/10.1597/1545-1569(1990)027%3C0193%3Atpfmsf%3E2.3.co%3B2

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