Flume tank characterization of marine current turbine blade behaviour under current and wave loading

Gaurier, Benoît; Davies, Peter; Deuff, A.; Germain, Grégory

doi:10.1016/j.renene.2013.02.026

Cited by 93 publications

(63 citation statements)

References 14 publications

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“…These results have shown that bursts of CTKE induce higher structural loads at scales 6%e23% of the rotor diameter on both stiff and flexible-blade wind turbines. Although observations of loads are not available for a tidal turbine (loads have been measured in a flume tank [43,44] but not in the field), Reynolds stresses, TKE, and CTKE from ADV measurements can be used to infer expected loading events.…”

Section: Turbulence Intensity Turbulent Kinetic Energy and Coherentmentioning

confidence: 99%

Characterization of turbulence anisotropy, coherence, and intermittency at a prospective tidal energy site: Observational data analysis

et al. 2015

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a b s t r a c tAs interest in marine renewable energy increases, observations are crucial for understanding the environments that prospective turbines will encounter. Data from an acoustic Doppler velocimeter in Puget Sound, WA are used to perform a detailed characterization of the turbulent flow encountered by a turbine in a tidal strait. Metrics such as turbulence intensity, structure functions, probability density functions, intermittency, coherent turbulence kinetic energy, anisotropy invariants, and a new scalar measure of anisotropy are used to characterize the turbulence. The results indicate that the scalar anisotropy magnitude can be used to identify and parameterize coherent, turbulent events in the flow. An analysis of the anisotropy characteristics leads to a physical description of turbulent stresses as being primarily one-or two-dimensional, in contrast to isotropic, three-dimensional turbulence. A new measure of the anisotropy magnitude is introduced to quantify the level of anisotropic, coherent turbulence in a coordinate-independent way. These diagnostics and results will be useful for improved realism in modeling the performance and loading of turbines in realistic ocean environments.

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Section: Turbulence Intensity Turbulent Kinetic Energy and Coherentmentioning

confidence: 99%

Characterization of turbulence anisotropy, coherence, and intermittency at a prospective tidal energy site: Observational data analysis

et al. 2015

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“…Further, numerical simulations have shown how turbulence affects the wake recovery behind an actuator disc turbine representation [11]. Studies using model turbine rotors have also shown significant variations when operated in flows with different turbulence intensities [12]- [14]. It has been found that increasing turbulence intensity from 3-15% typically reduces the power and thrust coefficients of a 3 bladed turbine rotor by roughly 5-10% [13].…”

Section: Introductionmentioning

confidence: 99%

Effects of turbulence on tidal turbines: Implications to performance, blade loads, and condition monitoring

Blackmore

Myers

Bahaj

2016

International Journal of Marine Energy

126

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Laboratory scale testing of tidal turbines has generated valuable datasets to support optimised turbine design and numerical model validation. However, tidal sites are highly turbulent with a broad range of length scales and turbulence intensities that are site specific. In this work we describe an experimental campaign using static grids to generate turbulence and investigate its impact on a model tidal turbine in a circulating water flume. Length scales, energy spectra and turbulence dissipation rates are first considered for centre point measurements before full flow characterisation of the ambient conditions across the turbine rotor area. Six different cases were chosen to observe the performance of a 1/20 th scale 0.8m diameter turbine subjected to these flows. The rotor thrust and torque, and flapwise and edgewise blade root bending moments were measured. It was found that the thrust and power coefficients were sensitive to the estimate of ambient velocity. In the most extreme case the Betz limit could be 'exceeded' depending on which estimate of ambient velocity was used. Overall variations in the peak power coefficient of over 10% were observed, demonstrating the significance turbulence has on turbine performance. It was also found that there is a strong correlation between fluctuations in blade root bending moments and the rotor loads. As a result we proposed that fatigue loads acting on the blades may be estimated from the fluctuations in power output of the turbine. Therefore maintenance operations maybe optimised from real-time fatigue monitoring of blade loads without the need to install additional instrumentation on the turbine blades. Under this proposed regime the cost of energy will be reduced due to reductions in turbine costs and following optimisation of the maintenance requirements and operational costs. This could also improve turbine reliability which would have significant implications for large multi turbine arrays.

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“…In another study, [10] presented interesting turbine performance and thrust curves, mainly oriented towards blade loads owing to oscillatory flows, similarly to [11] and [12]. Whilst some of those experimental results were used as a basis for numericalexperimental validation such as [13] and [14], none of them follow a standard experimental 25 protocol.…”

mentioning

confidence: 99%

Tidal energy “Round Robin” tests comparisons between towing tank and circulating tank results

Gaurier

Germain

Facq

et al. 2015

International Journal of Marine Energy

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One key step of the industrial development of a tidal energy device is the testing of scale prototype devices within a controlled laboratory environment. At present, there is no available experimental protocol which addresses in a quantitative manner the differences which can be expected between results obtained from the different types of facilities currently employed for this type of testing. As a consequence, where differences between results are found it has been difficult to confirm the extent to which these differences relate to the device performance or to the test facility type.In the present study, a comparative "Round Robin" testing programme has been conducted as part of the EC FP VII MaRINET program in order to evaluate the impact of different experimental facilities on the test results. The aim of the trials was to test the same model tidal turbine in four different test facilities to explore the sensitivity of the results to the choice of facility. The facilities comprised two towing tanks, of very different size, and two circulating water channels.Performance assessments in terms of torque, drag and inflow speed showed very similar results in all facilities. However, expected differences between the different tank types (circulating and towing) were observed in the fluctuations of torque and drag measurements. The main facility parameters which can influence the behaviour of the turbine were identified; in particular the effect of blockage was shown to be significant in cases yielding for high thrust coefficients, even at relatively small blockage ratios.

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Flume tank characterization of marine current turbine blade behaviour under current and wave loading

Cited by 93 publications

References 14 publications

Characterization of turbulence anisotropy, coherence, and intermittency at a prospective tidal energy site: Observational data analysis

Characterization of turbulence anisotropy, coherence, and intermittency at a prospective tidal energy site: Observational data analysis

Effects of turbulence on tidal turbines: Implications to performance, blade loads, and condition monitoring

Tidal energy “Round Robin” tests comparisons between towing tank and circulating tank results

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