Publications

Showing 11 out of 82 publications matching your search

Improving tidal turbine efficiency using winglets

The cost effectiveness of a tidal stream turbine can be improved by maximising the power extracted for a given rotor diameter. This paper presents a numerical and experimental study showing that winglets could be used to this end. The numerical simulations were conducted using Tornado, a vortex lattice code, which can model the interaction between different spanwise sections unlike Blade Element Momentum methods. Tornado was used to identify the important winglet design parameters such as dihedral angle. Tornado cannot capture viscous effects and so an experimental study was conducted on four designs. These were tested on a small-scale horizontal axis turbine in the Ifremer flume tank. The impact of winglets on the blade spanwise flow was found to have a significant effect on the amount of loss generated. The inviscid code used in this paper could complement existing quasi-3D design tools.

Authors:

Young, A. , Smyth, A., Bajpai, V., Augarde, R., Farman, J., and Sequeira, C.

Publication:

In proceedings from the 13th European Wave and Tidal Energy Conference, Napoli, Italy

The Effect of 3D Geometry on Unsteady Gust Response, Using a Vortex Lattice Model

Authors:

Smyth, A. S. M., Young, A. M. and Di Mare, L.

Publication:

AIAA Scitech 2019 Forum, San Diego, California

DOI:

https://doi.org/10.2514/6.2019-0899

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An unsteady pressure probe for the measurement of flow unsteadiness in tidal channels

An unsteady five-hole probe has been developed for the measurement of turbulent flow in tidal channels. Such measurements are vital for accurate prediction of unsteady loads on tidal turbines. Existing field-based velocimeters are either unable to capture the required range of frequencies or are too expensive to profile the variation of turbulence across a typical tidal power site. This work adapts the traditional five-hole wind tunnel probe to achieve a low-cost device with sufficient frequency range for tidal turbine applications. The main issue in the marine environment is that the ambient hydrostatic pressure is much higher than the dynamic pressure. This has been overcome by using novel calibration coefficients and differential transducers. In flume tank tests against laser Doppler velocimeter measurements, the frequency response of the probe has been shown to be sufficient to capture all the frequencies necessary for tidal turbine design.

Authors:

Young, A., Clark, C., Atkins, N., and Germain, G.

Publication:

IEEE Journal of Oceanic Engineering

DOI:

https://doi.org/10.1109/JOE.2019.2933131

Three-Dimensional Unsteady Hydrodynamic Modelling of Tidal Turbines

Authors:

Smyth, A., and Young, A.

Publication:

In proceedings from the 13th European Wave and Tidal Energy Conference, Napoli, Italy

DOI:

https://doi.org/10.17863/CAM.40077

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A one-dimensional model for tidal array design based on three-scale dynamics

Authors:

Gupta, V. and Young, A. M.

Publication:

Journal of Fluid Mechanics

DOI:

https://doi.org/10.1017/jfm.2017.399

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Wireless RF telemetry for rotating frame data acquisition and control

Obtaining measurements in the rotating frame of reference requires either real-time communication between the rotating and stationary frames, or temporary data storage in the rotating frame. Rotating telemetry systems must be low-noise and high-bandwidth, which is hard to achieve using traditional slip-ring arrangements, while using temporary data storage introduces synchronisation issues. In this paper, the use of wireless telemetry for real-time data acquisition is demonstrated for two applications: tidal turbine load control and large-scale turbine pressure measurements.

Authors:

Farman, J.R.

Publication:

In proceedings of the XXIII Biannual Symposium on Measuring Techniques in Turbomachinery

DOI:

https://doi.org/10.17863/CAM.40671

Novel usage of five-hole probes: Tidal channel turbulence measurements

Authors:

Young, A., Guion, R., Atkins, N. and Costan, J.,

Publication:

In proceedings of the XXIII Biannual Symposium on Measurement Techniques in Turbomachinery

Load alleviation technology for extending life in tidal turbines

Authors:

Young, A., Farman, J., and Miller, R.

Publication:

In proceedings of the International Conference on Renewable Energies Offshore, Lisbon, Portugal

Unsteady Gust Response of Tidal Stream Turbines

This paper investigates the limitations of 2D linear unsteady aerofoil theory for modelling the unsteady gust response of tidal stream turbines. Accurate unsteady load prediction is required to determine turbine life. Current state of the art design codes in industry use a single model, based on Theodorsen’s theory, to predict the response to all types of gust. This paper shows that different types of gust require different types of model. Vortical gusts, such as due to turbulence and shear flows, should be modelled using a combination of Sears’ and Horlock’s theories. Pressure gusts, such as those caused by free surface waves, should be modelled using Loewy’s theory. The accuracy of these models is examined using numerical predictions. The range of gusts likely to occur at real tidal sites is also examined. In most likely situations, pressure gusts cause variations in loads which can be modelled quasi-steadily,but vortical gusts must be modelled using the combined Sears/Horlock theory

Authors:

Sequeira, C., and Miller, R.

Publication:

In proceedings of the OCEANS'14 MTS/IEEE conference, St. John's, Canada

The frequency response of acoustic doppler current profilers: Spatiotemporal response and implicatio

Authors:

Guion, R. and Young, A.

Publication:

IEEE Oceans

DOI:

10.1109/OCEANS.2014.7003057

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