Effect of a 2D Hill on the Propagation of Wind Turbine Noise

TL;DR

This study uses numerical simulations to analyze how a 2D hill affects wind turbine noise propagation, revealing that terrain topography significantly influences sound focusing and attenuation.

Contribution

The paper introduces a numerical modeling approach combining linearized Euler equations and large-eddy simulations to study terrain effects on wind turbine noise.

Findings

Wind turbine wake acts as a waveguide focusing sound towards the ground.

Terrain topography, especially hills, significantly alters noise propagation patterns.

Sound focusing occurs closer to the turbine with increased wind speed.

Abstract

A good understanding of wind turbine noise propagation is relevant to better measure the impact of turbines on the environment. In this study, we developed numerical simulations to study the impact of a 2D hill on the sound propagation for a turbine in non flat terrain. The simulations employed a propagation model derived from the linearized Euler equations, solved in a moving frame following the wavefront. The wind turbine noise was modeled using a point source approach. The flow structure in the atmospheric boundary layer and the wind turbine wake were obtained from large-eddy simulations. We find that the wind turbine wake acts as a waveguide that focuses sound propagation towards the ground. This effect is most pronounced for the flat terrain case and when the turbine is placed on the hill. The sound attenuation is more localized and closer to the turbine when the wind turbine is placed on the hilltop than in the flat case. As the wind speed increases, the sound focusing is observed closer to the turbine. For a turbine placed in front of the hill, the sound propagation is mainly determined by the flow over the hill. This demonstrates that terrain topography can have surprising effects on wind turbine noise propagation.