Bernoulli Effect

This entry describes the Bernoulli effect, named after the 18th-century Swiss mathematician and physicist Daniel Bernoulli, which is the force that keeps aeroplanes in the air and allows sailing boats to tack against the wind. Its relevance to speech is that it is implicated in the trilling actions of the vocal folds in voicing and of the lips and tongue in trill sounds such as [b, r, r].

Figure 1 Bernoulli Effect and the Voicing Cycle

The basis of the effect is that the pressure of a flowing fluid (gas or liquid) decreases at right angles to the direction of flow in proportion as the velocity of flow increases. Surfaces adjacent to the flow tend to get sucked into it (see Figure 1). In the case of ...