Development of an Efficient Numerical Method for Wind Turbine Flow, Sound Generation, and Propagation under Multi-Wake Conditions

Zhenye Sun,Jens Sørensen,Emre Barlas,Jiufa Cao,Wei Zhu,Wen Shen,Hua Yang

doi:10.3390/app9010100

Zhenye Sun, Jens Sørensen + Show 5 more

Open Access

https://doi.org/10.3390/app9010100

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Abstract

The propagation of aerodynamic noise from multi-wind turbines is studied. An efficient hybrid method is developed to jointly predict the aerodynamic and aeroacoustics performances of wind turbines, such as blade loading, rotor power, rotor aerodynamic noise sources, and propagation of noise. This numerical method combined the simulations of wind turbine flow, noise source and its propagation which is solved for long propagation path and under complex flow environment. The results from computational fluid dynamics (CFD) calculations not only provide wind turbine power and thrust information, but also provide detailed wake flow. The wake flow is computed with a 2D actuator disc (AD) method that is based on the axisymmetric flow assumption. The relative inflow velocity and angle of attack (AOA) of each blade element form input data to the noise source model. The noise source is also the initial condition for the wave equation that solves long distance noise propagation in frequency domain. Simulations were conducted under different atmospheric conditions which showed that wake flow is an important part that has to be included in wind turbine noise propagation.

Highlights

The generation and propagation of wind turbine aerodynamic noise exhibit several special characteristics as compared to some other industrial noise problems
Combing the flowfield aerodynamic simulation and the aeroacoustics computation of multiwind turbines is the focus of this paper
The numerical computations are carried out using the in-house developed tool EllipSys

Summary

Introduction

The generation and propagation of wind turbine aerodynamic noise exhibit several special characteristics as compared to some other industrial noise problems. Considering the generation of wind turbine aerodynamic noise, the rotor aerodynamic noise level depends on airfoil profiles at cross sections, blade shape (the spanwise distribution of chord, twist, and airfoils), rotor size, rotational speed, yaw angle, tilt angle, pitch setting, the angular position of blades, wind speed profile, inflow turbulence level, density, and viscosity of air. From the perspective of aerodynamic noise propagation (ANPropagation), aerodynamic noise source (ANSource) of large wind turbines is often located at high altitude which leads to more significant problem for ANPropagation over long range. The study of wind turbine noise is a multi-disciplinary subject which should consider wind farm aerodynamic noise generation (ANGeneration), ANPropagation, and energy production.

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