Bernoulli’s airflow across curved lips initiates their vibration

Evidence

Soon after they are momentarily shut, the folds are forced open again by air pressure and flow from the lungs. As they are blown open, the folds acquire some velocity and momentum, causing them to continue to open, but like an oscillator, they resist stretching with an opposing tension. They reach a maximum opening and stretch, but the ensuing elastic rebound causes them to close, and the cycle then repeats. It is often stated that the Bernoulli effect (pressure is lower where air is flowing faster, as it is when it passes by the folds) is responsible for their closing, but this only part of the effect, probably more important for soft singing. The role of the elasticity and acquired momentum of the membranes (that is, the oscillator characteristics) involved should not be overlooked. Like an oscillator, the folds under a given tension and held at a given separation have a resonance frequency, which becomes the drive frequency for the vocal tract. For conversation, this drive frequency averages 100 to 125 Hz for males and 210 Hz for females; children average over 300 Hz. — Eric J. Heller, Why You Hear What You Hear- An…, 1661 (#contradicts, via linked claim)

Categorization

• XREF: connects to: The Bernoulli effect couples airflow velocity to reduced pressure at constrictions; Lift on curved surfaces comes from a pressure gradient, not the Bernoulli effect; Lip vibration self-sustains through Bernoulli pressure and elastic recoil (+8 more)

Broader Connections

• Lip vibration self-sustains through Bernoulli pressure and elastic recoil #corroborates (1.00)
• The Bernoulli effect is a wrong explanation for vocal fold vibration #contradicts (0.95) — Eric J. Heller, Why You Hear What You Hear- An…, 1661
• Elastic lips sustain oscillation only when energy is continuously input #expands (0.85)
• Elastic recoil and momentum, not Bernoulli effect, mainly close the vocal folds #qualifies (0.85)
• The lip drive’s nonlinear interaction with pressure waves complicates the treble picture #qualifies (0.80)
• Trumpet valves combine with lip synchronization to expand pitch range #complicates (0.75)
• Nonlinear vibration generates new frequencies absent from the original stimulus #complicates (0.75)