NREL wind turbine aerodynamics validation and noise predictions using a Lattice Boltzmann Method

Abstract

The 3-D design and optimization of wind-turbine blades remains a challenging task for computational fluid simulations both in term of aerodynamics and aeroacoustics. In this paper, flow and noise simulations are performed on a full-scale 2-blade wind-turbine tested at the National Renewable Energy Laboratory. The Lattice Boltzmann Method is used to predict the unsteady flow around the wind-turbine at different operating conditions corresponding to various inflow speeds. From these unsteady calculations, the normal force coefficient, the mean torque and the pressure coefficient at multiple locations on the blades are extracted and compared to experiments. The far-field noise is estimated by coupling the blade and tower wall-pressure fluctuations to a Ffowcs-Williams and Hawking’s equation solver. The analysis of the surface pressure fluctuations in the frequency domain and the turbulent flow in the vicinity of the blade gives an insight on the noise sources responsible for the tonal noise radiation.