  Sound production due to turbulence is widely shown to be an important
phenomenon involved in a.o. fricatives, singing, whispering and speech
pathologies. In spite of its relevance turbulent flow is not considered in
classical physical speech production models mostly dealing with voiced sound
production. The current study presents preliminary results of an experimental
validation of simplified turbulence models in order to estimate the time-mean
velocity distribution in a free jet downstream of a tube outlet. Aiming a
future application in speech production the influence of typical vocal tract
shape parameters on the velocity distribution is experimentally and
theoretically explored: the tube shape, length and the degree and geometry of
the constriction. Simplified theoretical predictions are obtained by applying
similarity solutions of the bidimensional boundary layer theory to a plane and
circular free jet in still air. The orifice velocity and shape are the main
model input quantities. Results are discussed with respect to the upper airways
and human sound production.
