Experimental Aeroacoustics Analysis of Vertical Axis Wind Turbine

Abstract

Wind energy is one of the rich and clean renewable resources to deal with energy crises and global warming. Mainstreaming of this form of energy has produced the possibility of making wind turbines a part of the urban landscape. The noise from the vertical axis wind turbine (VAWT) is the main issue. Therefore, it is essential to analyze the parameters which can help to reduce noise. The aerodynamic performance of a VAWT has been significantly improved by efficient blade design and with different arrangements of blades. In this work, a new design of VAWTs is present for the reduction of noise generation. This study focuses on measuring acoustic signals on a 3-bladed VAWT in a nonresonant chamber at different TSR (tip speed ratio) using a microphonic array. In biplane and tandem VAWT every blade is constructed using two airfoils. In this work blade with different spacing has been studied. The SPL results of the spectrum of VAWT inferred that tonal noises such as blade passing frequencies are leading at lower frequencies whereas broadband noise harmonizes to all distinct ranges of frequencies. The result of the spacing between the blades shows that in biplane VAWT 21% and in tandem 60% is the best arrangement for noise reduction. Also, the major portion of noise from the source is influenced by aerodynamic noises generated due to flow separation.