Aerodynamic Noise Prediction Of Horizontal Axis Wind Turbine

The development of wind energy in the world is flourishing because it is a kind of absolutely clean and renewable energy. But with the fast increase of wind energy development, it also gives rise to the problems concerning public acceptance of wind energy. The noise is the main drawback. The noise from wind turbines may annoy people who live around. This problem becomes especially serious due to the fact that wind turbines are densely covered in many areas. Therefore it's necessary to estimate the noise level in the field where the wind turbines are installed.Generally, the noise from wind turbine is composed with mechanical noise and aerodynamic noise. The mechanical noise is caused by the different operating machine elements which can be reduced efficiently by many engineering methods. However, the way to reduce aerodynamic noise from wind turbines is a bit complex which should be studied more. Through the years, several models have been proposed to explain and predict wind turbine noise.Some of the models make use of complex CFD solvers that have not yet matured to be applied in practice. As a compromise between computing speed and accuracy, the most commonly used models are based on semi-empirical relations.Main contents of this thesis are described as the following:1. Employ the experimental results on airfoil self-noise by Brooks, Pope and Marcolini, together with the turbulence inflow model proposed by Lowson. The model was tested successfully against the measurement result.2. Analyze the effect of turbulence intensity and pitch angle on sound pressure level of wind turbine aerodynamic noise and present effective methods of predicting and reducing wind turbine aerodynamic noise.3. Du-Selig stall delay model is used to improve the performance prediction accuracy. But the calculation results have shown the stall delay model have little effect on the prediction accuracy.