Aerodynamic and aeroacoustic performance assessment of H-rotor darrieus VAWT equipped with wind-lens technology

Abstract

The present paper investigates the aerodynamic and aeroacoustic characteristics of H-rotor Darrieus vertical axis wind turbine combined with a promising energy conversion technology, namely wind-lens, employing computational approaches. The Darrieus turbine adequate for low wind speed and urban area conditions. However, its aerodynamic and aeroacoustic characteristics are very complicated. Thus, the main scope of the current work is to enhance the aerodynamic performance of the introduced turbine and then assess the noise production accomplished with such enhancement. The studies are taken on two phases, the first phase is parametric 2D CFD simulations, employing the unsteady Reynolds-averaged Navier-Stokes (URANS) approach, to optimize the design parameters of the wind-lens. The second phase is a 3D CFD simulation of the full turbine using a higher order numerical scheme employing a hybrid RANS/LES method. An estimate of the aeroacoustic noise of the turbine is quantified using the Ffowcs Williams-Hawkings (FW-H) method. As a result, the optimal design parameters of the wind-lens are achieved and the optimized configuration shows a superior augmentation in power generated of about 82% increase in the power coefficient at a speed ratio of 2.75. However, the turbine equipped wind-lens produces more noisy operation compared to the non-shrouded turbine.