Vortex shedding from aircraft surfaces is both loud and a drag source

Evidence

The engine is not the only noisemaker on a modern aircraft. Vortices are shed near many of the wing, tail, and body surfaces, often loudly, with frequencies in the audio range. The same vortices are also a source of drag, so aerodynamicists do double-duty if they can control them. — Eric J. Heller, Why You Hear What You Hear- An…, 1346

Categorization

• XREF: Connects to the reader’s noise-ecology interests and prior material on aircraft noise regulation.