An overview of aerodynamic performance analysis of vertical axis wind turbines

In this paper, an attempt has been made to highlight major developments of vertical axis wind turbines (VAWTs) in the last few decades. The effects of various design parameters such as airfoil, number of blades, solidity, aspect ratio, blade helicity, and overlap ratio have been critically analyzed. Wind energy is the most promising renewable, cost-effective, efficient, and accessible source for both domestic and commercial applications. Horizontal axis wind turbines are highly developed and are being used for medium-to-large scale power projects. VAWT are considered viable options for urban and semi-urban areas. These turbines have several characteristics, such as omnidirectional, power generation in weak and unstable winds, esthetically sound, safety, and low noise. Darrieus turbines with a fixed blade-type have starting problems at low wind speeds. Savonius turbines have good starting capability; however, their power coefficients are lower than other types of VAWT. To overcome the shortcomings of conventional wind turbines, an innovative engineering solution was sought in the design of hybrid VAWT. The analysis revealed that hybrid wind turbines have addressed the deficiencies to an extent; however, the overall performance is still less than that of conventional wind turbines. Several recommendations have been made based on state-of-the-art information from the perspective of future studies and acceptability. It was concluded that vast opportunities for wind turbine applications are available in urban areas; however, further academic research is required on critical aspects such as self-starting at low wind speeds, efficiency, structural reliability, design improvement for aerodynamic performance, and wind resource assessment.