Jet instability makes it easy for resonance to control vortex timing

Evidence

The instability of the jet makes it susceptible to control, and the Helmholtz oscillations just outside the mouth easily provide the slight push needed to control the vortices. — Eric J. Heller, Why You Hear What You Hear- An…, 1308

Categorization

• XREF: The ‘controllable instability’ idea parallels how aeroelastic feedback works in other flow-driven oscillators.