Split Control Wind Turbine Airfoil noise with CFD and Acoustic Analogies

Abstract

This research aims to investigate the impact of a split airfoil on noise emissions from a horizontal-axis wind turbine. The objective is to comprehensively understand the airflow patterns around the airfoil to reduce noise emissions. The study rigorously examines a range of angles of attack, from 0° to 25°, for both the original airfoil and the airfoil with a split, using advanced computational aerodynamics coupled with analog acoustic analysis. The methodology involves two-dimensional flow simulations with Delayed Detached Eddy Simulation based on the Spalart-Allmaras model, enabling precise near-field flow calculations around the airfoil. Additionally, far-field noise predictions, employing the Ffowcs Williams and Hawkings analogy based on simulated sources, reveal the efficacy of the split airfoil design. Results indicate that the split airfoil design effectively reduces noise emissions across various angles of attack. These reductions translate into a significant decrease in the Overall Sound Pressure Level, ranging from 14% to 19%, and remarkable Sound Pressure Level reductions between 12% and 60% across diverse frequencies, showcasing substantial noise improvements in various frequency ranges.