The phrase "whirring sound" means a noise that sounds like something spinning or rotating very quickly.
Sentences with «whirring sound»
UPPER MANHATTAN — Uptown residents tired of the constant whirring sound of helicopters flying overheard are mounting a petition against what they say is an excessive flight pattern. (dnainfo.com)
Check for the characteristic, but momentary, whirring sound from the in - tank fuel pump at key «on». (yourmechanic.com)
A few minutes later I noticed a tinny whirring sound and then a clicking, and that's when I started to panic. (ktmade.com)