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- Amrutha and Kumar
Ocean wave energy is one of the cleanest renewable energy sources around the globe, but wave energy varies widely from place to place and from time to time. The long-term variability of wave power at 20 locations in the Indian shelf seas from 1979 to 2018 is described here using the European Centre for Medium-Range Weather Forecasts recently released ERA5 reanalysis hourly data. The…
- Khan et al.
The energy in flowing river streams, tidal currents or other artificial water channels is being considered as viable source of renewable power. Hydrokinetic conversion systems, albeit mostly at its early stage of development, may appear suitable in harnessing energy from such renewable resources. A number of resource quantization and demonstrations have been conducted throughout the world and…
- Epps et al.
Marine hydrokinetic turbines are a promising source of renewable energy, but the costs of existing cross-flow turbine designs are too high. In order to develop new designs with reduced costs, there exists a need for a low-order computational model that is simultaneously fast, accurate, and robust. Herein, we present a novel theoretical model for the analysis of cross-flow propellers and…
- Zhang et al.
A modified Savonius hydrokinetic rotor was proposed. Flows near the rotor were measured using the time-resolved particle image velocimetry (TR-PIV) technique. Effects of the rotor angle and upstream velocity were described. The rotor geometry was further optimized and the rotor performance was evaluated using the computational fluid dynamics (CFD) technique. The two aspects were dedicated…
- Guerra et al.
Significant effort has been devoted to the study of marine turbine wakes using numerical models and laboratory experiments. Recent deployments of full-scale hydrokinetic turbines in rivers and tidal channels provide new opportunities to map these wakes in the field, contributing to the development and validation of such models. However, efficient field methods that can accurately map the…
- Bachant
Cross-flow (often vertical-axis) turbines (CFTs), despite being thoroughly investigated and subsequently abandoned for large scale wind energy, are seeing renewed interest for smaller scale wind turbine arrays, offshore wind, and marine hydrokinetic (MHK) energy applications. Though they are similar to the large scale Darrieus wind turbines, today’s CFT rotors are often designed with higher…
- Bachant and Wosnik
Minimizing wake losses in wind or marine hydrokinetic (MHK) turbine arrays is a crucial design consideration, as it has a large impact on overall energy production. To understand and mitigate these losses, interactions between turbine wakes must be accurately predicted, with near-wakes being especially important for cross-flow (or vertical-axis) turbines, given their affinity for close-spaced…
- Hill et al.
The Reference Model Project, sponsored by the U.S. Department of Energy’s Wind and Water Power Technologies Program, aims at expediting industry growth and efficiency by providing nonproprietary point designs of marine hydrokinetic (MHK) technologies as Reference Models (RM) for open-source research and development [1]. As part of this program, two reference MHK turbine models were tested at…
- Bachant et al.
The mechanical power, total rotor drag, and near-wake velocity of a 1:6 scale model (1.075 m diameter) of the US Department of Energy’s Reference Model vertical-axis cross-flow turbine were measured experimentally in a towing tank, to provide a comprehensive open dataset for validating numerical models. Performance was measured for a range of tip speed ratios and at multiple Reynolds numbers…
- Talukdar et al.
The vertical-axis helical-bladed hydrokinetic turbine serves as a viable source of renewable power that can extract kinetic energy of the free flowing water to generate electricity. Such helical-bladed turbines are characterized by lesser pulsation of torque and marginally favorable starting capability as compared to straight-bladed turbines. The present study aims at evaluating the…
- Gaurier et al.
This Round Robin Test program aims to establish the influence of the combined wave and current effect on the power capture and performance of a generic tidal turbine prototype. Three facilities offering similar range of experimental conditions have been selected on the basis that their dimensions along with the rotor diameter of the turbine translate into low blockage ratio conditions. The…
- Liu et al.
With the large progress in tidal current energy, the size of tidal current turbine (TCT) rotors has increased, leading to more substantial asymmetrical loads. In this study, severe asymmetrical loads were investigated by a sea trial experiment with a 600-kW two-bladed horizontal-axis TCT. Individual pitch control (IPC) has been recommended and validated to be effective for load reductions.…
- Nicholls-Lee et al.
Free stream tidal turbines are rotating bodies in fast flowing tidal currents, and as such are exposed to fluctuating loads from the surrounding fluid. These time varying forces will cause the blades to deform dynamically, potentially deflecting the blade shape away from the optimum orientation as well as exciting resonant responses that may enhance fatigue loading. It is important to…
- Rajaram et al.
The fatigue behaviour of carbon fibre reinforced polymer (CFRP) under the dry and hygrothermal aged conditions was investigated at two stress ratios, 0.1 and 0.5. Two types of layup, named as the unconstrained [06], and constrained [±45/03]S laminates were investigated to understand the ‘constraining effect’ on the zero-degree plies, imposed by the ±45 plies of the constrained laminate. The…
- Bittencourt et al.
As part of the ReDAPT, a project commissioned and co-funded by the ETI (Energy Technologies Institute), the first standard for certification of horizontal axis tidal turbine (HATT) has been commissioned to DNV GL in order to accelerate the development of the tidal technology and its commercialization. Although the development of the standard is limited to one turbine concept and unlike the…
- Allsop
The predictable nature of the tides offers a regular, reliable source of renewable energy that can be harnessed using tidal stream turbines (TSTs). The UK's practically extractable tidal stream energy resource has the potential to supply around 7 % of the country's annual electricity demand. As of 2016, the world's first commercial scale arrays have been deployed around the UK and France. The…
- Ullah et al.
The tidal power has the potential to play a vital role in a sustainable energy future. The main objective of this paper is to investigate the performance and fatigue life of tidal current turbine (TCT) using fluid structure interaction (FSI) modeling. The performance of TCT was predicted using Ansys CFX. The performance curve, pressure distribution on the blade, and velocity streamline were…
- Senat
Marine current turbines are submerged structures and subjected to loading conditions from both the currents and wave effects. The associated phenomena posed significant challenge to the analyses of the loading response of the rotor blades and practical limitations in terms of device location and operational envelopes. The effect of waves on marine current turbines can contribute to the change…
- Erdogan et al.
This paper describes the dynamic models of the complete power take-off system (PTO) for grid-connected tidal energy systems and performs its real-time simulation on a parallel hardware platform. It is aimed at (i) validating the system concept by showing if the operational performance and limits of the PTO meet the requirements set by the turbine, (ii) providing the realtime simulation as a…
- Kirke and Lazauskas
Small Darrieus hydrokinetic turbines with fixed pitch blades typically suffer from poor starting torque, low efficiency and shaking due to large fluctuations in both radial and tangential force with azimuth angle. Efficiency improves as size increases, since adequate blade chord Reynolds numbers can be maintained with low solidity. Shaking can be eliminated by using helical blades, or reduced…
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