scholarly journals Interactions between tidal turbine wakes: experimental study of a group of three-bladed rotors

2013 ◽  
Vol 371 (1985) ◽  
pp. 20120159 ◽  
Author(s):  
T. Stallard ◽  
R. Collings ◽  
T. Feng ◽  
J. Whelan
Keyword(s):  
Experimental Study ◽  
Free Surface ◽  
Horizontal Axis ◽  
Incident Flow ◽  
Velocity Reduction ◽  
Tidal Turbine ◽  
Tidal Stream ◽  
Rate Of Recovery ◽  
Bounding Surfaces ◽  
Tidal Stream Turbine

It is well known that a wake will develop downstream of a tidal stream turbine owing to extraction of axial momentum across the rotor plane. To select a suitable layout for an array of horizontal axis tidal stream turbines, it is important to understand the extent and structure of the wakes of each turbine. Studies of wind turbines and isolated tidal stream turbines have shown that the velocity reduction in the wake of a single device is a function of the rotor operating state (specifically thrust), and that the rate of recovery of wake velocity is dependent on mixing between the wake and the surrounding flow. For an unbounded flow, the velocity of the surrounding flow is similar to that of the incident flow. However, the velocity of the surrounding flow will be increased by the presence of bounding surfaces formed by the bed and free surface, and by the wake of adjacent devices. This paper presents the results of an experimental study investigating the influence of such bounding surfaces on the structure of the wake of tidal stream turbines.

Experimental study of the wake homogeneity evolution behind a horizontal axis tidal stream turbine

2021 ◽  
Vol 111 ◽  
pp. 102644
Author(s):  
Zhi Zhang ◽  
Yuquan Zhang ◽  
Jisheng Zhang ◽  
Yuan Zheng ◽  
Wei Zang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Horizontal Axis ◽  
Tidal Stream ◽  
Tidal Stream Turbine

scholarly journals Experimental study of wake structure behind a horizontal axis tidal stream turbine

2017 ◽  
Vol 196 ◽  
pp. 82-96 ◽  
Author(s):  
Yaling Chen ◽  
Binliang Lin ◽  
Jie Lin ◽  
Shujie Wang
Keyword(s):  
Experimental Study ◽  
Horizontal Axis ◽  
Wake Structure ◽  
Tidal Stream ◽  
Tidal Stream Turbine

Experimental study on kinetic energy conversion of horizontal axis tidal stream turbine

2016 ◽  
Vol 97 ◽  
pp. 784-797 ◽  
Author(s):  
Jeonghwa Seo ◽  
Seung-Jae Lee ◽  
Woo-Sik Choi ◽  
Sung Taek Park ◽  
Shin Hyung Rhee
Keyword(s):  
Experimental Study ◽  
Kinetic Energy ◽  
Energy Conversion ◽  
Horizontal Axis ◽  
Tidal Stream ◽  
Tidal Stream Turbine

Numerical Investigation of an Optimised Horizontal Axis Tidal Stream Turbine

2019 ◽  
Author(s):  
Hassan El Sheshtawy ◽  
Ould el Moctar ◽  
Thomas E. Schellin ◽  
Satish Natarajan
Keyword(s):  
Output Power ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Speed Ratio ◽  
Navier Stokes Equations ◽  
Tidal Turbines ◽  
Tidal Turbine ◽  
Sst Turbulence Model ◽  
Tidal Stream ◽  
Tidal Stream Turbine

Abstract A tidal stream turbine was designed using one of the optimised hydrofoils, whose lift-to-drag ratio at an angle of attack of 5.2 degrees was 4.5% higher than that of the reference hydrofoil. The incompressible Reynolds-averaged Navier Stokes equations in steady state were solved using k-ω (SST) turbulence model for the reference and optimised tidal stream turbines. The discretisation errors and the effect of different y+ values on the solution were analysed. Thrust and power coefficients of the modelled reference turbine were validated against experimental measurements. Output power and thrust of the reference and the optimised tidal turbines were compared. For a tip speed ratio of 3.0, the output power of the optimised tidal turbine was 8.27% higher than that of the reference turbine of the same thrust.

Multi-fidelity optimization of blade thickness parameters for a horizontal axis tidal stream turbine

2019 ◽  
Vol 135 ◽  
pp. 277-287 ◽  
Author(s):  
P. Madhan Kumar ◽  
Jeonghwa Seo ◽  
Woochan Seok ◽  
Shin Hyung Rhee ◽  
Abdus Samad
Keyword(s):  
Horizontal Axis ◽  
Blade Thickness ◽  
Tidal Stream ◽  
Tidal Stream Turbine

Demonstrating a Tidal Turbine Control Strategy at Laboratory Scale

2016 ◽  
Author(s):  
Magnus Harrold ◽  
Peter Bromley ◽  
Merin Broudic ◽  
David Clelland
Keyword(s):  
Control Strategy ◽  
Cost Effective ◽  
Scale Model ◽  
Turbine Performance ◽  
Controller Gain ◽  
Tidal Turbine ◽  
Tidal Stream ◽  
Commercial Device ◽  
Tidal Stream Turbine ◽  
Thrust Forces

Ahead of the installation of a commercial tidal stream turbine, a 1:30 scale model of the device was tested in a recirculating flume tank. This proved to be the first physical demonstration of the turbine’s unconventional control strategy, which limits the thrust forces on the device by allowing the rotor to enter an overspeed. The tests showed that this simple to implement concept of operation is a cost-effective and reliable means of managing the rotor thrust loads in energetic flows. Subsequent tests highlighted the importance of correctly calculating the controller gain parameter, otherwise detrimental turbine performance characteristics can be expected. When relating these results to that of the commercial device, there are a number of important differences associated with both the environment and scale of the model tests. Despite this, the results are considered encouraging, and provided confidence for the full-scale deployment.

scholarly journals Tidal Stream vs. Wind Energy: The Value of Cyclic Power When Combined with Short-Term Storage in Hybrid Systems

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1106
Author(s):  
Daniel Coles ◽  
Athanasios Angeloudis ◽  
Zoe Goss ◽  
Jon Miles
Keyword(s):  
Hybrid Systems ◽  
Hybrid System ◽  
Carbon Emissions ◽  
Short Term ◽  
Operating Life ◽  
Power Cycling ◽  
Tidal Turbine ◽  
Tidal Stream ◽  
Wind Resource ◽  
Tidal Stream Turbine

This study quantifies the technical, economic and environmental performance of hybrid systems that use either a tidal stream or wind turbine, alongside short-term battery storage and back-up oil generators. The systems are designed to partially displace oil generators on the island of Alderney, located in the British Channel Islands. The tidal stream turbine provides four power generation periods per day, every day. This relatively high frequency power cycling limits the use of the oil generators to 1.6 GWh/year. In contrast, low wind resource periods can last for days, forcing the wind hybrid system to rely on the back-up oil generators over long periods, totalling 2.4 GWh/year (50% higher). For this reason the tidal hybrid system spends £0.25 million/year less on fuel by displacing a greater volume of oil, or £6.4 million over a 25 year operating life, assuming a flat cost of oil over this period. The tidal and wind hybrid systems achieve an oil displacement of 78% and 67% respectively (the same as the reduction in carbon emissions). For the wind hybrid system to displace the same amount of oil as the tidal hybrid system, two additional wind turbines are needed. The ability of the battery to store excess turbine energy during high tidal/wind resource periods relies on opportunities to regularly discharge stored energy. The tidal hybrid system achieves this during slack tides. Periods of high wind resource outlast those of high tidal resource, causing the battery to often remain fully charged and excess wind power to be curtailed. Consequently the wind hybrid system curtails 1.9 GWh/year, whilst the tidal turbine curtails 0.2 GWh/year. The ability of the tidal stream turbines to reduce curtailment, fuel costs and carbon emissions may provide a case for implementing them in hybrid systems, if these benefits outweigh their relatively high capital and operating expenditure.

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