The effect of turbulence on noise emissions from a micro-scale horizontal axis wind turbine

Building mounted micro wind turbines are capable of contributing a significant proportion to a building’s energy needs in the right circumstances. However the introduction of this technology in built-up areas has been limited due to a number of issues such as low wind speeds, high turbulence and noise issues. This paper presents the results of an investigation carried out to assess the effect of turbulence on the noise emissions from a micro-scale horizontal axis wind turbine (HAWT). Two experiments were devised in order to investigate the noise emissions from a Micro Wind Turbine (MWT) mounted on one of the University of Nottingham’s renewable energy monitoring platform. The first experiment measured the one-third octave sound levels to quantify the sound spectrum for the MWT. The second experiment assessed the effects of turbulence on the noise emissions from the same MWT. This paper describes in detail both of these methodologies. Results found that a doubling of the turbulence intensity from 0.3 to 0.6 resulted in an almost doubling of the sound energy level.

► We examine the connection between turbulence and noise for small-scale wind turbines mounted in the built environment.
► We briefly review sound propagation from wind turbines.
► Methodologies for monitoring noise and turbulence are presented.
► Results suggested that an increase in turbulence from 0.3 to 0.6 results in a doubling of the sound level.