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 orlfice geometry.
A.S.M.E. (1959). Flow measurement. Chapter 4 of Part 5. Supplement to ASME Power Test Codes.New York: The American Society of Mechanical Engineers.
2.
BjörkL. (1961). Velopharyngeal function in connected speech. Studies using tomography and cineradiographic synchronized with speech spectrography.Acta Radiol, Suppl202: 31–89.
3.
CreagerW.P. (1950). Hydraulics. In: SalisburyJ.K. ed. Kent's mechanical engineers handbook, power volume, twelfth edition.New York: John Wiley and Sons. 1–86.
4.
CroftC.B., ShprintzenR.J., RakoffS.J. (1981). Patterns of velopharyngeal valving in normal and cleft palate subjects: a multi-view videofluoroscopic and nasendoscopic study.Laryngoscope91: 265–271.
5.
IsshikiN., HonjowI., MorimotoM. (1968). Effects of velopharyngeal incompetence upon speech.Cleft Palate J5: 297–310.
6.
McWilliamsB.J., GlasserE.R., PhillipsB.J., LawrenceC., LavoratoA.S., BeeryQ.C., SkolnickM.L. (1981). A comparative study of four methods of evaluating velopharyngeal adequacy.Plast Reconstr Surg68: 1–9.
7.
OsbergP.E., WitzelM.A. (1981). The physiologic basis for hypernasality during connected speech in cleft palate patients: a nasendoscopic study.Plast Reconstr Surg67: 1–5.
8.
ShprintzenR.J. (1983). An invited commentary on the preceding article by Ibuki. Karnell and Morris.Cleft Palate J20: 105–107.
9.
ShprintzenR.J., Golding-KushnerK. (1989). Evaluation of velopharyngeal insufficiency. In: Healy G, Friedman E, eds. North American clinics in otolaryngology.Philadelphia: WB Saunders:22: 519–536.
10.
Siegel-SadewitzV.L., ShprintzenR.J. (1986). Changes in velopharyngeal valving with age.Int J Pediatr Otorhinolaryngol11: 171–182.
11.
SkolnickM.L. (1970). Videotluoroscopic examination of the velopharyngeal portal during phonation in lateral and base projections — a new technique for studying mechanics of closureCleft Palate J7: 803–816.
12.
SkolnickM.L., McCallG.N., BarnesM. (1973). The sphincteric mechanism of velopharyngeal closure.Cleft Palate J10: 286–305.
13.
SkolnickM.L., ShprintzenR.J., McCallG.N., RakoffS. (1975). Patterns of velopharyngeal closure in subjects with repaired cleft palate and normal speech: a multi-view videofluoroscopic analysis.Cleft Palate J12: 369–376.
14.
SmithB.E., WeinbergB. (1980). Prediction of velopharyngeal orifice area: a re-examination of model experimentation.Cleft Palate J17: 277–282.
15.
VennardJ.K., StreetR.L. (1975). Elementary fluid mechanics.New York: John Wiley and Sons, 521–579.
16.
WarrenD.W., DevereuxJ.L. (1966). An analog study of cleft palate speech.Cleft Palate J3: 103–114.
17.
WarrenD.W., DuboisA.B. (1964). A pressure-flow technique for measuring velopharyngeal orifice area during continuous speech.Cleft Palate J1: 52–71.
18.
DekkerE. (1961). Transition between laminar and turbulent flow in the human trachea.J Appl Physiol16: 1060–1064.
19.
HixonT. (1966). Turbulent noise sources for speech.Folia Phoniatr18: 168–182.
20.
LubkerJ.F. (1969). Velopharyngeal orifice area: a replication of analog experimentation.J Speech Hear Res12: 218–222.
21.
Müllerem, BrownW.S. (1980). Variations in the supraglottal air pressure waveform and their articulatory interpretations. In: LassN.J., ed. Speech and language advances in basic research and practice. Vol. 4. New York: Academic Press. 317–389.
22.
ReynoldsO. (1883). An experimental investigation of the circumstances which determine whether the motion of water shall be direct or sinuous and the law of resistance in parallel channels.Philos Trans R Soc Lond174: 935.
23.
SchererR.C. (1988). Fluid mechanics of the velopharyngeal tract.J Acoust Soc Am83: 5112.
24.
SelleyW.G., ZananiriM.C., EllisR.E., FlackF.C. (1987). The effect of tongue position on division of airflow in the presence of velopharyngeal defects.Br J Plast Surg40: 377–383.
25.
SmithB.E., MoonJ.B., WeinbergB. (1984). The effects of increased nasal airway resistance on modeled velopharyngeal orifice area estimation, Cleft Palate J21: 172–180.
26.
SmithB.E., WeinbergB. (1980). Prediction of velopharyngeal orifice area: a reexamination of model experimentation.Cleft Palate J17: 277–282
27.
SmithB.E., WeinbergB. (1982). Prediction of modeled velopharyngeal orifice areas during steady flow conditions during aerodynamic simulation of voiceless stop consonants.Cleft Pa late J19: 172–180.
28.
SmithB.E., WeinbergB. (1983). Velopharyngeal orifice area prediction during aerodynamic simulation of fricative consonants.Cleft Palate J20: 1–7.
29.
WarrenD.W., DalstonR.M., Morrke, HairfieldW.M., SmithL.R. (1989). The speech regulating system: temporal and aerodynamic responses to velopharyngeal inadequacy.J Speech Hear Res32: 566–575.
30.
WarrenD.W., DevereuxJ.L. (1966). An analog study of cleft palate speech.Cleft Palate J3: 103–114.
31.
WarrenD.W., DuboisA.B. (1964). A pressure-flow technique for measuring velopharyngeal orifice area during continuous speech.Cleft Palate J1: 52–71.
32.
WarrenD.W., HofmannF.A. (1961). A cineradiographic study of velopharyngeal closure.Plast Reconstr Surg28: 656–669.
33.
WarrenD.W., RyonW.E. (1967). Oral port constriction, nasal resistance, and respiratory aspects of cleft palate speech: an analog study.Cleft Palate J4: 38–46.
34.
WestJ.B., Hugh-JonesP. (1959). Patterns of gas flow in the upper bronchial tree.J Appl Physiol14: 753–759.
