Low-cost wind turbine aeroacoustic predictions using actuator lines

TL;DR

This paper introduces a low-cost, coupled CFD and acoustic prediction methodology for wind turbine noise, combining actuator line simulations with a fast noise model validated against real turbine measurements.

Contribution

It develops a computationally efficient approach that integrates actuator line CFD with a rapid acoustic prediction method considering detailed turbine geometry.

Findings

Method accurately predicts wind turbine noise levels.

Validation shows good agreement with field measurements.

Approach reduces computational costs significantly.

Abstract

Aerodynamic noise is a limitation for further exploitation of wind energy resources. As this type of noise is caused by the interaction of turbulent flow with the airframe, a detailed resolution of the flow is necessary to obtain an accurate prediction of the far-field noise. Computational fluid dynamic (CFD) solvers simulate the flow field but only at a high computational cost, which is much increased when the acoustic field is resolved. Therefore, wind turbine noise predictions using numerical approaches remain a challenge. This paper presents a methodology that couples (relatively fast) wind turbine CFD simulations using actuator lines with a fast turn-around noise prediction method. The flow field is simulated using actuator lines and large eddy simulations. The noise prediction method is based on the Amiet-Schlinker's theory for rotatory noise sources, considering leading- and trailing-edge noise as unique noise sources. A 2D panel code (XFOIL) calculates the sectional forces and boundary layer quantities. The resulting methodology for the noise prediction method is of high fidelity since the wind turbine geometry is accounted for in both flow and acoustics predictions. Results are compared with field measurements of a full-scale wind turbine for two operational conditions, validating the results of this research.