scholarly journals Spar-Type Vertical-Axis Wind Turbines in Moderate Water Depth: A Feasibility Study

Energies ◽  
2018 ◽  
Vol 11 (3) ◽  
pp. 555 ◽  
Author(s):  
Ting Wen ◽  
Kai Wang ◽  
Zhengshun Cheng ◽  
Muk Ong

The applications of floating vertical-axis wind turbines (VAWTs) in deep water have been proposed and studied by several researchers recently. However, the feasibility of deploying a floating VAWT at a moderate water depth has not yet been studied. In this paper, this feasibility is thoroughly addressed by comparing the dynamic responses of spar-type VAWTs in deep water and moderate water depth. A short spar VAWT supporting a 5 MW Darrieus rotor at moderate water depth is proposed by following the deep spar concept in deep water. A fully coupled simulation tool, SIMO-RIFLEX-DMS code, is utilized to carry out time domain simulations under turbulent wind and irregular waves. Dynamic responses of the short spar and deep spar VAWTs are analyzed and compared, including the natural periods, wind turbine performance, platform motions, tower base bending moments, and tension of mooring lines. The statistical characteristics of the thrust and power production for both spars are similar. The comparison of platform motions and tower base bending moments demonstrate a good agreement for both spars, but the short spar has better performance in surge/sway motions and side–side bending moments. The 2P response dominates the bending moment spectra for both spars. A significant variation in tension of Mooring Line 1 and a larger corresponding spectrum value are found in the short spar concept. The results indicate that the application of short spar VAWTs is feasible and could become an alternative concept at moderate water depth.

2018 ◽  
Author(s):  
D. Todd Griffith ◽  
Matthew F. Barone ◽  
Joshua Paquette ◽  
Brian Christopher Owens ◽  
Diana L. Bull ◽  
...  

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8000
Author(s):  
Abel Arredondo-Galeana ◽  
Feargal Brennan

The offshore wind sector is expanding to deep water locations through floating platforms. This poses challenges to horizontal axis wind turbines (HAWTs) due to the ever growing size of blades and floating support structures. As such, maintaining the structural integrity and reducing the levelised cost of energy (LCoE) of floating HAWTs seems increasingly difficult. An alternative to these challenges could be found in floating offshore vertical axis wind turbines (VAWTs). It is known that VAWTs have certain advantages over HAWTs, and in fact, some small-scale developers have successfully commercialised their onshore prototypes. In contrast, it remains unknown whether VAWTs can offer an advantage for deep water floating offshore wind farms. Therefore, here we present a multi-criteria review of different aspects of VAWTs to address this question. It is found that wind farm power density and reliability could be decisive factors to make VAWTs a feasible alternative for deep water floating arrays. Finally, we propose a way forward based on the findings of this review.


Wind Energy ◽  
2016 ◽  
Vol 20 (2) ◽  
pp. 305-323 ◽  
Author(s):  
Zhengshun Cheng ◽  
Kai Wang ◽  
Zhen Gao ◽  
Torgeir Moan

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2286
Author(s):  
Yutaka Hara ◽  
Yoshifumi Jodai ◽  
Tomoyuki Okinaga ◽  
Masaru Furukawa

To investigate the optimum layouts of small vertical-axis wind turbines, a two-dimensional analysis of dynamic fluid body interaction is performed via computational fluid dynamics for a rotor pair in various configurations. The rotational speed of each turbine rotor (diameter: D = 50 mm) varies based on the equation of motion. First, the dependence of rotor performance on the gap distance (gap) between two rotors is investigated. For parallel layouts, counter-down (CD) layouts with blades moving downwind in the gap region yield a higher mean power than counter-up (CU) layouts with blades moving upwind in the gap region. CD layouts with gap/D = 0.5–1.0 yield a maximum average power that is 23% higher than that of an isolated single rotor. Assuming isotropic bidirectional wind speed, co-rotating (CO) layouts with the same rotational direction are superior to the combination of CD and CU layouts regardless of the gap distance. For tandem layouts, the inverse-rotation (IR) configuration shows an earlier wake recovery than the CO configuration. For 16-wind-direction layouts, both the IR and CO configurations indicate similar power distribution at gap/D = 2.0. For the first time, this study demonstrates the phase synchronization of two rotors via numerical simulation.


Author(s):  
Xiaomin Chen ◽  
Ramesh Agarwal

In this paper, we consider the Wind Farm layout optimization problem using a genetic algorithm. Both the Horizontal–Axis Wind Turbines (HAWT) and Vertical-Axis Wind Turbines (VAWT) are considered. The goal of the optimization problem is to optimally place the turbines within the wind farm such that the wake effects are minimized and the power production is maximized. The reasonably accurate modeling of the turbine wake is critical in determination of the optimal layout of the turbines and the power generated. For HAWT, two wake models are considered; both are found to give similar answers. For VAWT, a very simple wake model is employed.


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