Influence of tidal parameters on SeaGen flicker performance

MacEnri, J.; Reed, M.; Thiringer, Torbjörn

doi:10.1098/rsta.2012.0247

Cited by 39 publications

(33 citation statements)

References 3 publications

(5 reference statements)

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“…4 where u 02 versus u is shown. Similarly, MacEnri et al [38] saw the same behavior, but with lower overall turbulence intensity levels in the Strangford Lough, Ireland. This variation in I u encourages further analysis into what causes the turbulence intensity to peak, since the large spread suggests that local values of u are not a good predictor of s u .…”

Section: Turbulence Intensity Turbulent Kinetic Energy and Coherentmentioning

confidence: 51%

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: 51%

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

et al. 2015

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“…These include information varying across annual and seasonal time scales to fluctuations in velocity at time scales of seconds and below, with different scales of motion understood to have varying effects on energy extraction devices [10]. Similarly, knowledge of the spatial variation of flow parameters is required across a wide range, from orders of tens of blade diameters for, e.g., power curve production [11] to variations of metres and below for investigations into device loading and blade fatigue [12,13] and quality of power [14]. No single instrument system at present can economically provide the measurements required to meet the multi-scale nature of tidal flows.…”

Section: Tidal Site Characterisation For Tidal Energy Applicationsmentioning

confidence: 99%

Characterisation of Tidal Flows at the European Marine Energy Centre in the Absence of Ocean Waves

et al. 2018

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Abstract:The data analyses and results presented here are based on the field measurement campaign of the Reliable Data Acquisition Platform for Tidal (ReDAPT) project (Energy Technologies Institute (ETI), U. K. 2010-2015). During ReDAPT, a 1 MW commercial prototype tidal turbine was deployed and operated at the Fall of Warness tidal test site within the European Marine Energy Centre (EMEC), Orkney, U.K. Mean flow speeds and Turbulence Intensity (TI) at multiple positions proximal to the machine are considered. Through the implemented wave identification techniques, the dataset can be filtered into conditions where the effects of waves are present or absent. Due to the volume of results, only flow conditions in the absence of waves are reported here. The analysis shows that TI and mean flows are found to vary considerably between flood and ebb tides whilst exhibiting sensitivity to the tidal phase and to the specification of spatial averaging and velocity binning. The principal measurement technique was acoustic Doppler profiling provided by seabed-mounted Diverging-beam Acoustic Doppler Profilers (D-ADP) together with remotely-operable Single-Beam Acoustic Doppler Profilers (SB-ADP) installed at mid-depth on the tidal turbine. This novel configuration allows inter-instrument comparisons, which were conducted. Turbulence intensity averaged over the rotor extents of the ReDAPT turbine for flood tides vary between 16.7% at flow speeds above 0.3 m/s and 11.7% when considering only flow speeds in the turbine operating speed range, which reduces to 10.9% (6.8% relative reduction) following the implementation of noise correction techniques. Equivalent values for ebb tides are 14.7%, 10.1% and 9.3% (7.9% relative reduction). For flood and ebb tides, TI values resulting from noise correction are reduced in absolute terms by 3% and 2% respectively across a wide velocity range and approximately 1% for turbine operating speeds. Through comparison with SB-ADP-derived mid-depth TI values, this correction is shown to be conservative since uncorrected SB-ADP results remain, in relative terms, between 10% and 21% below corrected D-ADP values depending on tidal direction and the range of velocities considered. Results derived from other regions of the water column, those important to floating turbine devices for example, are reported for comparison.

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“…The blades were oriented on T1 and T2 so that the lift-induced torque would cause clockwise and anti-clockwise rotations, respectively, thus forming the contra-rotating pair shown in Figure 11. Each rotor was connected to a modelled generator, and like SeaGen, these generators operated asynchronously [66]. The mesh resolution was highest near the blades and reduced gradually with distance from the rotors, as can be seen in Figure 12.…”

Section: Configurationsmentioning

confidence: 99%

Effects of Support Structures in an LES Actuator Line Model of a Tidal Turbine with Contra-Rotating Rotors

2017

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Abstract:Computational fluid dynamics is used to study the impact of the support structure of a tidal turbine on performance and the downstream wake characteristics. A high-fidelity computational model of a dual rotor, contra-rotating tidal turbine in a large channel domain is presented, with turbulence modelled using large eddy simulation. Actuator lines represent the turbine blades, permitting the analysis of transient flow features and turbine diagnostics. The following four cases are considered: the flow in an unexploited, empty channel; flow in a channel containing the rotors; flow in a channel containing the support structure; and flow in a channel with both rotors and support structure. The results indicate that the support structure contributes significantly to the behaviour of the turbine and to turbulence levels downstream, even when the rotors are upstream. This implies that inclusion of the turbine structure, or some parametrisation thereof, is a prerequisite for the realistic prediction of turbine performance and reliability, particularly for array layouts where wake effects become significant.

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Influence of tidal parameters on SeaGen flicker performance

Cited by 39 publications

References 3 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

Characterisation of Tidal Flows at the European Marine Energy Centre in the Absence of Ocean Waves

Effects of Support Structures in an LES Actuator Line Model of a Tidal Turbine with Contra-Rotating Rotors

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