whirring

/ˈwɜrɪŋ/
adjective
  1. Making a continuous, low, buzzing or humming sound.
    • She watched the whirring blades of the helicopter.
    • The whirring blender mixed the smoothie in seconds.
    • A whirring noise came from the engine.
noun
  1. A continuous, low, buzzing or humming sound, like that made by something spinning fast.
    • I could hear the whirring of the drone as it flew overhead.
    • The old computer made a loud whirring when it started up.
    • The whirring of the fan helped me fall asleep.