Prediction methodologies for tonal and broadband noise from horizontal‐axis wind turbines.

This paper describes a set of computational‐analytic predictive tools for the following mechanisms of aerodynamic sound and vibration for a wind turbine’s blades in ducted or open arrangements: (a) Infrasound and tonal low‐frequency nearfield noise from the interaction of blades with a nonuniform meanflow that is steady in its own reference frame; (b) mid‐frequency broadband noise from the “haystacked” chopping of an incident turbulent freestream; (c) high‐frequency noise from self‐generated turbulence near the trailing edge of each blade’s suction side. Contributors to tonal mechanism (a) include the rotor’s static loads as required by power generation (nearfield “Gutin” component of infrasound), and operation in a local wind shear or in the mean wake of the turbine’s tower when set up as a downstream machine. These predictive tools include models of the spatially nonuniform mean and turbulent flows that typically strike a wind turbine’s blades, as well as preprocessors of that information when made avai...