A novel method of vertical axis wind turbine noise prediction

Vertical Axis Wind Turbines are becoming more commonplace in urban environments but to date there has not been much computational work done to quantify their noise outputs. The EU FP7 project: SWIP (New innovative solutions, components and tools for the integration of wind energy in urban and peri-urban areas) aims to deal with, and overcome, the main barriers that slow down the largescale deployment of small and medium size wind turbines. One of the outputs of the project is a novel, six bladed, vertical axis wind turbine rated at 2kW. This work aims to predict aeroacoustic noise generated by the SWIP vertical axis wind turbine by means of a novel noise prediction method. Due to the high computational cost of LES an approach is proposed in which ANSYS Fluent is used to determine the transient flow solution, using unsteady RANS calculation, on a 2D section of the wind turbine undergoing rotation. Acoustic signals are calculated by employing a MATLAB code which uses the CFD solution as input data into a semi-empirical solver based a number of airfoil noise prediction algorithms. The 2D CFD data is interpolated onto a 3D model of the turbine using a quasi-steady time stepping approach. An estimate of the aeroacoustic noise of the turbine is established and the sensitivity of the code to changes in time step and discretisation is considered.