Mechanisms of amplitude modulation in wind turbine noise

Malcom Smith , Andrew Bullmore , Matthew Cand , Robert Davis

The noise produced by wind turbines is inherently time varying. This amplitude modulation is normally due to the directivity of the dominant trailing edge noise sources combined with the changing position and orientation of the rotating blades. In some circumstances the level and character of the amplitude modulation is altered and this paper outlines results from a Renewable UK funded research programme into the possible causes. Besides the variability of the normal trailing edge noise mechanism, other factors investigated include the possibility of blade stall or increased levels of inflow turbulence under some wind conditions combined with various propagation factors such as the effect of wind gradients and atmospheric absorption.

Mots clés: wind; turbine; amplitude; modulation

Domaines: Acoustique [physics.class-ph]

Malcom Smith, Andrew Bullmore, Matthew Cand, Robert Davis. Mechanisms of amplitude modulation in wind turbine noise. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00811262⟩