scispace - formally typeset

Topic

Tip-speed ratio

About: Tip-speed ratio is a(n) research topic. Over the lifetime, 1621 publication(s) have been published within this topic receiving 22072 citation(s).
Papers
More filters

Journal ArticleDOI
01 Mar 2007-Renewable Energy
Abstract: The results of cavitation tunnel and tank tests on an 800 mm diameter model of a marine current turbine (MCT) are presented. The tests were carried out in a 2.4 m×1.2 m cavitation tunnel and the 60 m towing tank. Results for power and thrust coefficients are presented for a range of tip speed ratio and pitch settings for various conditions. The results of this investigation provided an insight into the operation of a singe turbine in straight or yawed flow, the effect on performance of changes in the tip immersion of the rotor, the interference between twin rotors and the likely areas of cavitation inception. In addition, the analysed results presented provide useful information for the hydrodynamic design of MCTs and detailed data for the validation of numerical models.

598 citations


Journal ArticleDOI
Abstract: Increased concern for environment has led to the search for more environment friendly sources of energy. Wind energy can be a viable option in this regard. Vertical axis wind turbines offer promising solution for areas away from the integrated grid systems. However, they have certain drawbacks associated with different configurations. This paper reviews various configurations of VAWT along with their merits and demerits. Moreover, design techniques employed for VAWT design have also been reviewed along with their results. It was learned that coefficient of power (CP) for various configurations is different and can be optimized with reference to Tip Speed Ratio. Latest emerging design techniques can be helpful in this optimization. Furthermore, flow field around the blade can also be investigated with the help of these design techniques for safe operation.

347 citations


Journal ArticleDOI
01 Aug 2011-Energy
Abstract: This paper presents a CFD model for the evaluation of energy performance and aerodynamic forces acting on a straight-bladed vertical-axis Darrieus wind turbine. The basic principles which are currently applied to BE-M theory for rotor performance prediction are transferred to the CFD code, allowing the correlation between flow geometric characteristics (such as blade angles of attack) and dynamic quantities (such as rotor torque and blade tangential and normal forces). The model is proposed as a powerful design and optimization tool for the development of new rotor architectures for which test data is not available. After describing and validating the computational model against experimental data, a full campaign of simulation is proposed for a classical NACA 0021 three-bladed rotor. Flow field characteristics are investigated for several values of tip speed ratio, allowing a comparison among rotor operation at optimum and lower C p values, so that a better understanding of vertical-axis wind turbines basic physics is obtained.

340 citations


Journal ArticleDOI
TL;DR: The proposed sliding-mode control approach has been validated on a 1.5-MW three-blade wind turbine using the national renewable energy laboratory wind turbine simulator FAST (Fatigue, Aerodynamics, Structures, and Turbulence) code and results show that the proposed control strategy is effective in terms of power regulation.
Abstract: This paper deals with the power generation control in variable-speed wind turbines. These systems have two operation regions which depend on wind turbine tip speed ratio. A high-order sliding-mode control strategy is then proposed to ensure stability in both operation regions and to impose the ideal feedback control solution in spite of model uncertainties. This control strategy presents attractive features such as robustness to parametric uncertainties of the turbine. The proposed sliding-mode control approach has been validated on a 1.5-MW three-blade wind turbine using the national renewable energy laboratory wind turbine simulator FAST (Fatigue, Aerodynamics, Structures, and Turbulence) code. Validation results show that the proposed control strategy is effective in terms of power regulation. Moreover, the sliding-mode approach is arranged so as to produce no chattering in the generated torque that could lead to increased mechanical stress because of strong torque variations.

317 citations


Journal ArticleDOI
Abstract: This paper presents a review on the performance of Savonius wind turbines. This type of turbine is unusual and its application for obtaining useful energy from air stream is an alternative to the use of conventional wind turbines. Simple construction, high start up and full operation moment, wind acceptance from any direction, low noise and angular velocity in operation, reducing wear on moving parts, are some advantages of using this type of machine. Over the years, numerous adaptations for this device were proposed. The variety of possible configurations of the rotor is another advantage in using such machine. Each different arrangement of Savonius rotor affects its performance. Savonius rotor performance is affected by operational conditions, geometric and air flow parameters. The range of reported values for maximum averaged power coefficient includes values around 0.05–0.30 for most settings. Performance gains of up to 50% for tip speed ratio of maximum averaged power coefficient are also reported with the use of stators. Present article aims to gather relevant information about Savonius turbines, bringing a discussion about their performance. It is intended to provide useful knowledge for future studies.

257 citations


Network Information
Related Topics (5)
Wind power

99K papers, 1.5M citations

83% related
Renewable energy

87.6K papers, 1.6M citations

78% related
Photovoltaic system

103.9K papers, 1.6M citations

76% related
Electric power system

133K papers, 1.7M citations

73% related
Heat transfer

181.7K papers, 2.9M citations

70% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20226
2021121
2020118
2019140
2018130
2017115