An Aeroacoustic Analysis of Wind Turbines

Abstract

This paper describes computational aeroacoustic methods that are being applied to predict the noise radiated by wind turbines. Since the wind turbine noise problem is very challenging, only some of the important noise sources and mechanisms are being considered. These are airfoil self-noise, the effects of blade rotation, and the propagation of sound over large distances. Two aspects of airfoil self-noise are being studied. The first is the relatively low frequency noise generated by deep stall and the second is trailing edge noise. The noise associated with blade rotation includes the effects of blade rotation on the blade aerodynamics, incoming gusts, incoming atmospheric turbulence and wind shear. The unsteady flow simulations are coupled to the radiated noise field with the permeable surface Ffowcs Williams -Hawkings formulation. For longrange noise propagation predictions, methods based on solutions of the linearized Euler equations or the Parabolic Equation approximation are discussed. Alternative methods for the implementation of boundary conditions for the propagation studies are also included.

Advances in Measuring Noise from Wind Turbines

“…shows a wider field of view from the same array location as the previous figures to include the contribution from Turbine M71 (395 m from the array) in addition to M72.Data produced in such experiments can validate computational aeroacoustics programs such as the one in Ref 16…”

Wind Turbines: Clean, Renewable and Quiet?

“…We can also use aeroacoustics principles to calculate noise radiation from unsteady aerodynamic sources. [15][16][17][18][19] Since wind-turbine noise can affect the health and quality of life of nearby residents and animal populations, for widespread growth of wind turbine farms to be feasible, we must optimize blade designs for flow characteristics and minimum noise under various conditions, including gusting.…”

Aeroacoustics response of wind turbine blade profiles in normal and icing conditions

“…Ewert and Schröder (2004) applied a hybrid method based on LES of compressible flow and acoustic perturbation equations to predict trailing edge noise. Morris et al (2004) used computational fluid dynamics (CFD) approach to study several computational aeroacoustics (CAA) techniques that offer considerable promise for the prediction of noise from wind turbines.…”