This research presents an experimental study on a scaled prototype of a bladeless wind turbine that operates based on the principle of vortex-induced vibrations (VIV-BWT) with the implementation of bio-inspired design of a columnar-cactus type mast. The aerodynamic performance of columnar-cactus type masts with different numbers of ribs was investigated and compared with that of a conventional cylindrical mast. The objective of this novel proposal is to maximize wind energy conversion efficiency through vortex-induced vibrations, thereby enhancing energy generation. The present study focuses on the geometry of the columnar-cactus type mast as a vortex generator, which significantly influences the performance of this type of VIV wind energy harvester. The findings reveal that the geometric configuration of the cactus-inspired mast and the mast angle promote vortex formation, leading to higher lift coefficients and forces. Consequently, this results in greater vortex-induced vibration magnitudes. For instance, at a wind speed of 6.0 m/s and a mast angle of 0°, the 6-rib cactus-type mast exhibits 12 times greater VIV amplitude compared to the conventional cylindrical mast, while the 5-rib and 7-rib cactus-type masts show 2.4- and 2.2-times greater amplitudes, respectively. However, for wind speeds below 5 m/s, the cylindrical mast demonstrates superior VIV performance.

The research presents the calculation by numerical methods of the energy density for a typical vertical wind profile, which is obtained from data acquired by the Regional Center for Wind Technology (CERTE) in the region of Juchitán de Zaragoza, Oaxaca, Mexico. The vertical wind profile considered presents inhomogeneities in energy density and speed, unlike the controlled conditions in a laboratory with a wind tunnel. The energy density allows us to calculate correction factors on the measured parameters of a wind turbine when it is tested under free wind laboratory conditions. The correction factor for the power coefficient in a small wind turbine with a capacity to generate 30 kW of power, developed by CIATEQ AC Centro de Tecnología Avanzada, hypothetically measured under free wind conditions, is also shown. These correction factors can also be useful in estimating the power generated when laboratory conditions are not available.

There is wind energy in urban and rural areas that is not being used sufficiently; since the wind in these areas tends to be turbulent and slow. For this reason, this study is focused on the design and analysis of a vertical axis wind turbine based on the Darrieus type, which seeks to improve self-starting, since it is one of the main problems of this type of turbine. To achieve this, the study focuses on the first stage of self-starting, also known as static torque, which occurs at an angular velocity close to zero. This stage is essential for reaching the second stage of self-starting, known as dynamic torque. To do this, a two-blade 9W Darrieus-type turbine is designed and compared with the new blade design called “flow concentrator” considering the maximum height, maximum diameter, and chord of both as constants. The analysis is performed using the Double-multiple stream tube theorem (DMST), computational fluid dynamics (CFD), and by carrying out experimental tests. The results obtained are analyzed at different wind speeds, from 3 to 8 m/s, and at different azimuthal angle positions (0°, +45°, -45°, 90°), where a considerable improvement in self-starting of up to 100% is observed in its most optimal position.