Slewing Effect of Twin Vertical Axis Turbines Supported by a Floating Platform Able to Rotate Around a Single Mooring System

2018 ◽  
Author(s):  
Kazuma Kusanagi ◽  
Sharath Srinivasamurthy ◽  
Yasunori Nihei
Keyword(s):  
Wind Turbines ◽  
Wind Direction ◽  
Clean Energy ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Mooring System ◽  
Wind Condition ◽  
Vertical Axis Wind Turbines ◽  
New Type ◽  
New System

In this study, we propose a new and innovative solution for harnessing offshore wind using vertical axis wind turbines (VAWT). The new type of FOWT is termed as Twin connection VAWT which uses single point mooring system consisting of two turbines capable of aligning itself against any wind direction. New-type vertical axis wind turbines are designed and developed by some of the present authors which are supported by separate floaters. The conceptual development and working mechanism of the proposed Twin connection VAWT is described in this paper based on experimental results. The yawing motion of proposed system about the moored point aligning itself to the direction of wind is confirmed in a series of dedicated experiments under only-wind condition. After aligning itself and turbines facing the direction of the wind, slow varying slewing motion phenomenon is observed during experiments. The wind forces acting on two VAWTs is examined in x-y plane and it is predicted that the forces acting perpendicular to the wind direction explains the slewing phenomenon. A physics model is conceptualized and developed to understand the yawing mechanism of the new system. A numerical simulation code is also developed to understand the yaw motion around the moored point using the steering motion equations. It is confirmed how the new system proposed can be utilized for generating clean energy.

scholarly journals On mooring line tension and fatigue prediction for offshore vertical axis wind turbines: A comparison of lumped mass and quasi-static approaches

2018 ◽  
Vol 42 (2) ◽  
pp. 97-107 ◽  
Author(s):  
D Cevasco ◽  
M Collu ◽  
CM Rizzo ◽  
M Hall
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Line Tension ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Mooring Line ◽  
Offshore Wind Turbine ◽  
Vertical Axis Wind Turbine ◽  
Lumped Mass ◽  
Vertical Axis Wind Turbines

Despite several potential advantages, relatively few studies and design support tools have been developed for floating vertical axis wind turbines. Due to the substantial aerodynamics differences, the analyses of vertical axis wind turbine on floating structures cannot be easily extended from what have been already done for horizontal axis wind turbines. Therefore, the main aim of the present work is to compare the dynamic response of the floating offshore wind turbine system adopting two different mooring dynamics approaches. Two versions of the in-house aero-hydro-mooring coupled model of dynamics for floating vertical axis wind turbine (FloVAWT) have been used, employing a mooring quasi-static model, which solves the equations using an energetic approach, and a modified version of floating vertical axis wind turbine, which instead couples with the lumped mass mooring line model MoorDyn. The results, in terms of mooring line tension, fatigue and response in frequency have been obtained and analysed, based on a 5 MW Darrieus type rotor supported by the OC4-DeepCwind semisubmersible.

Hybrid/Combined Darrieus–Savonius Wind Turbines: Erstwhile Development and Future Prognosis

2021 ◽  
Vol 143 (5) ◽  
Author(s):  
Jyotirmoy Sarma ◽  
Siddhant Jain ◽  
Prasenjit Mukherjee ◽  
Ujjwal K. Saha
Keyword(s):  
Wind Turbines ◽  
Wind Direction ◽  
Review Paper ◽  
Past Research ◽  
Vertical Axis ◽  
Combined System ◽  
Future Studies ◽  
The Past ◽  
Vertical Axis Wind Turbines ◽  
Design Simplicity

Abstract Over the last few decades, the vertical-axis wind turbines (VAWTs) have undergone intensive research mainly due to their design simplicity and independency of wind direction. The drag-based Savonius wind rotor exhibits a better starting capability, whereas the lift-based Darrieus wind rotor achieves higher efficiency over a wider operating range. Thus, in order to capitalize on their advantages, both the rotors are mounted on the same axis to form a hybrid/combined system. In this review paper, an attempt has been made to collect and analyze the past research studies in the field of hybrid wind rotors. An optimization route has also been suggested for the design of such a hybrid wind rotor to ensure that the design complexity is minimized, and at the same time, both the Savonius and the Darrieus rotors are utilized to their fullest potential. In this regard, a few important parameters are identified whose effects on the hybrid rotor performance must be investigated in future studies. Suggestions and direction of research are presented keeping in mind the improvement of the technology.

scholarly journals Floating Offshore Vertical Axis Wind Turbines: Opportunities, Challenges and Way Forward

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8000
Author(s):  
Abel Arredondo-Galeana ◽  
Feargal Brennan
Keyword(s):  
Wind Turbines ◽  
Deep Water ◽  
Wind Farm ◽  
Structural Integrity ◽  
Wind Farms ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Small Scale ◽  
Offshore Wind Farms ◽  
Vertical Axis Wind Turbines

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.

Designing and Analyzing Savonius Wind Turbines

2019 ◽  
Author(s):  
Varun Kumar Reddy Manne ◽  
Hong Zhou
Keyword(s):  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Wind Turbines ◽  
Wind Direction ◽  
High Reliability ◽  
Power Conversion ◽  
Vertical Axis ◽  
Geometric Parameters ◽  
Vertical Axis Wind Turbines ◽  
Static Torque

Abstract Savonius wind turbines are drag-type vertical axis wind turbines. Their blades experience less drag while moving against the wind flow and more drag while moving in the wind direction. The drag difference rotates Savonius wind turbines and produces electrical power. Savonius wind turbines can catch wind from any direction. No yaw motion mechanism is needed for them to be pointed in the wind direction. Savonius wind turbines have simple structures and are convenient to install and maintain. They can operate on low wind speed and have good starting characteristics. Compared with horizontal axis wind turbines and lift-type vertical axis wind turbines such as Darrieus and Giromill wind turbines, Savonius wind turbines have relatively low power conversion efficiency. This is because of their drag-type nature which generates positive and negative torque on their advancing and returning blades, respectively. Savonius wind turbines are suitable for locations where power conversion efficiency can be compromised for the sake of low cost and high reliability. One major drawback from Savonius wind turbines is the negative static torque which lowers their self-starting ability. Although the negative static torque of Savonius wind turbines can be mitigated by adding additional components such as curtains, nozzles and ducts to them, these additional components make them complex and lose omnidirectional performance. In this paper, Savonius wind turbines are designed based on their geometric parameters to remove their negative static torque and improve their performance. Savonius wind turbines with different numbers of blades and other geometric parameters are designed, analyzed and simulated.

A Comparison of Two Coupled Model of Dynamics for Offshore Floating Vertical Axis Wind Turbines (VAWT)

2014 ◽  
Author(s):  
Michael Borg ◽  
Kai Wang ◽  
Maurizio Collu ◽  
Torgeir Moan
Keyword(s):  
Wind Turbines ◽  
Coupled Model ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Design Codes ◽  
Vertical Axis Wind Turbines ◽  
Complex Simulation ◽  
Floating Offshore Wind Turbines ◽  
Horizontal Axis Wind Turbines ◽  
Engineering Models

As part of the deployment of floating offshore wind turbines (FOWTs) in deep sea, robust coupled dynamic design codes based on engineering models are being developed to investigate the behaviour of FOWTs in the offshore environment. The recent re-emerging interest in vertical axis wind turbines (VAWTs) for floating foundation applications has resulted in a number of design codes being developed concurrently by different researchers. In this study, two such design codes for floating VAWTs developed at Cranfield University and the Norwegian University of Science and Technology are compared through a series of increasingly complex simulation load cases. A floating VAWT design was specified to be used in this study. The rotor is based on the Darrieus Troposkein shape and is the same used within the DeepWind VAWT spar concept, with a 5MW rated capacity. The floating support structure is a semi-submersible that is being used in the Offshore Code Collaboration Continuation (OC4) Phase II project for floating horizontal axis wind turbines. A series of load cases were set out to assess and compare the two different design codes. A comparison of the performance of the two design tools is presented, illustrating their level of maturity and areas of improvement.

Numerical Analysis of High-Rise Steel Structure with Wind Turbines under Earthquake Action

2013 ◽  
Vol 278-280 ◽  
pp. 216-219
Author(s):  
Ying Yang ◽  
Guo Ping Chen ◽  
Xiao Jun Guan
Keyword(s):  
Wind Turbines ◽  
Time History ◽  
Steel Structure ◽  
Vertical Axis ◽  
Mechanical Analysis ◽  
High Rise ◽  
Vertical Axis Wind Turbines ◽  
History Analysis ◽  
New Energy ◽  
New Type

The utilization of new energy sources, like wind power, has become more and more popular as the global energy crisis escalated. Preliminary mechanical analysis was done to verify the feasibility of a new type of building structure, integrated high-rise steel structure with vertical axis wind turbines. Time history analysis under the action of EI-Centro earthquake wave and Wenchuan earthquake wave were carried out on the model with wind turbines and the other one without. The seismic behavior of this new structure was analyzed.

scholarly journals Numerical Analysis of the Dynamic Interaction between Two Closely Spaced Vertical-Axis Wind Turbines

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2286
Author(s):  
Yutaka Hara ◽  
Yoshifumi Jodai ◽  
Tomoyuki Okinaga ◽  
Masaru Furukawa
Keyword(s):  
Wind Turbines ◽  
Power Distribution ◽  
Phase Synchronization ◽  
Average Power ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Mean Power ◽  
Vertical Axis Wind Turbines ◽  
Fluid Body ◽  
First Time

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.

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