University of Tasmania
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Wave-turbulence decomposition methods applied to tidal energy site assessment

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posted on 2023-05-21, 00:42 authored by Perez, L, Cossu, R, Couzi, C, Irene PenesisIrene Penesis
High levels of turbulence have been proven to substantially increase the blade loadings on tidal turbines, outlining the need of properly characterizing turbulence parameters in tidal energy sites. The presence of long surface gravity waves may cause a significant bias on the estimation of these parameters, which requires wave-turbulence decomposition methods that are currently missing from guidelines. Here, three techniques of decomposing wave and turbulence are tested: the stopband filter (SB), moving average filter (MA), and synchrosqueezing wavelet transform (SWT). The study site, Banks Strait, Tasmania, is a 16 km wide channel that presents high potential for tidal energy generation. Wave peak periods at the study site were found to vary mostly between 7 and 12 s, with maximum exceeding 15 s. Turbulence intensities (TI), turbulent kinetic energy (TKE), and integral scales are quantified. Our results indicate differences between the estimates obtained from each method. The MA highly underestimates turbulence, resulting in TI values which were nearly 50% lower than those obtained from other decomposition methods. While TI and TKE estimated from the SB and the SWT techniques are quite similar, integral length scales are considerably underestimated by the SB. These findings reveal that the SWT is a more reliable method because of the more accurate estimates of turbulence parameters and indicate the need of establishing guidelines which address wave-turbulence decomposition in tidal stream energy site assessments. Despite having shown to be quite a versatile technique, further investigation of its applicability in data from other prospective tidal energy sites is necessary to fully assess the generality of the SWT technique.

Funding

Australian Renewable Energy Agency

MAKO Tidal Turbines Pty Ltd

OpenHydro Group Ltd

Sabella SA

Spiral Energy Corporation Pty Ltd

University of Queensland

History

Publication title

Energies

Volume

13

Issue

5

Article number

1245

Number

1245

ISSN

1996-1073

Department/School

Australian Maritime College

Publisher

MDPIAG

Place of publication

Switzerland

Rights statement

Copyright 2020 by the authors. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/

Repository Status

  • Open

Socio-economic Objectives

Tidal energy

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    University Of Tasmania

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