ON THE PERFORMANCE OF VERTICAL AXIS WIND TURBINES IN STEADY WIND UNDER VARIOUS BLADE CAMBER LEVELS

Abstract

Vertical axis wind turbine (VAWT) has been shown to be more suited to small scale power production in the urban environment due to distinct advantages over its horizontal counterpart. Over the last few years, continuous improvement on its aerodynamic performance, either through experimental or numerical analysis, have been carried out by numerous researchers. VAWT performance was investigated using Computational Fluid Dynamics modeling. The influence of camber on steady wind performance was analyzed and the most efficient of all levels of blade camber studied for VAWT application was determined. Various levels of camber were imposed on to a NACA XX25 blade profile, namely: 0.5%; 1.5% (cambered close to the path of rotation); and 2%. Results revealed positive effect of incorporating a positive level of blade camber to VAWT design. The most favorable configuration for the VAWT under study was determined to be the camber level that causes the camber line to coincide with the path of the rotor rotation. The paper presents an in-depth discussion of the flow physics and wake dynamics, for the two wind cases of VAWTs, through flow visualizations and blade force analysis.