Experimental study of the turbulence intensity effects on marine current turbines behaviour. Part II: Two interacting turbines

Mycek, Paul; Gaurier, Benoît; Germain, Grégory; Pinon, Grégory; Rivoalen, Elie

doi:10.1016/j.renene.2013.12.048

Cited by 149 publications

(129 citation statements)

References 11 publications

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“…It is widely accepted that C T is an expression involving rotor thrust only, so C T presented in this paper are overestimated because drag force on the structure is not subtracted (e.g. as already shown in [16] and [19]). It should be noted that one undesirable side effect of this is that the results are 130 sensitive to the exact submersion of the turbine, and hence the length of the submerged part of the mast.…”

Section: Power and Thrust Measurementsmentioning

confidence: 90%

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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Section: Power and Thrust Measurementsmentioning

confidence: 90%

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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“…Higher turbulence levels can also be expected behind hills, something that increases the fatigue loads on the turbine but also reduces the extent of the near‐wake region and promotes the turbine wake recovery . The faster wake recovery is beneficial in cases where the wakes behind multiple wind turbines interact regardless of the local terrain topography. Similar to the wake effects seen behind a hill, the wake interference from an upstream wind turbine reduces the available wind speed and thereby degrade the performance of downstream turbines, although this effect decreases with increased turbine spacings.…”

Section: Introductionmentioning

confidence: 99%

A wind‐tunnel study of the wake development behind wind turbines over sinusoidal hills

2018

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In the present work, the wake development behind small‐scale wind turbines is studied when introducing local topography variations consisting of a series of sinusoidal hills. Additionally, wind‐tunnel tests with homogeneous and sheared turbulent inflows were performed to understand how shear and ambient turbulence influence the results. The scale of the wind‐turbine models was about 1000 times smaller than full‐size turbines, suggesting that the present results should only be qualitatively extrapolated to real‐field scenarios. Wind‐tunnel measurements were made by means of stereoscopic particle image velocimetry to characterize the flow velocity in planes perpendicular to the flow direction. Over flat terrain, the wind‐turbine wake was seen to slowly approach the ground while it propagated downstream. When introducing hilly terrain, the downward wake deflection was enhanced in response to flow variations induced by the hills, and the turbulent kinetic energy content in the wake increased because of the speed‐up seen over the hills. The combined wake observed behind 2 streamwise aligned turbines was more diffused and when introducing hills, it was more prone to deflect towards the ground compared to the wake behind an isolated turbine. Since wake interactions are common at sites with multiple turbines, this suggested that it is important to consider the local hill‐induced velocity variations when onshore wind farms are analysed. Differences in the flow fields were seen when introducing either homogeneous or sheared turbulent inflow conditions, emphasizing the importance of accounting for the prevailing turbulence conditions at a given wind‐farm site to accurately capture the downstream wake development.

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“…In this case, the inviscid-flow BIEM with VFC model is combined with a viscous flow solver (Reynolds-Averaged Navier-Stokes, RANS) to correctly describe the turbulent, vortical stream that characterizes the inflow to a turbine in the wake of similar devices placed upstream. An application of this combined BIEM-VFC and RANS computational methodology has been discussed by the authors in [27], where the interaction between two three-bladed turbines axially aligned with the upstream flow is analysed and numerical results are compared with experimental data from [28].…”

Section: Discussionmentioning

confidence: 99%

Marine Turbine Hydrodynamics by a Boundary Element Method with Viscous Flow Correction

Salvatore¹,

Sarichloo²,

Calcagni³

2018

JMSE

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A computational methodology for the hydrodynamic analysis of horizontal axis marine current turbines is presented. The approach is based on a boundary integral equation method for inviscid flows originally developed for marine propellers and adapted here to describe the flow features that characterize hydrokinetic turbines. For this purpose, semi-analytical trailing wake and viscous flow correction models are introduced. A validation study is performed by comparing hydrodynamic performance predictions with two experimental test cases and with results from other numerical models in the literature. The capability of the proposed methodology to correctly describe turbine thrust and power over a wide range of operating conditions is discussed. Viscosity effects associated to blade flow separation and stall are taken into account and predicted thrust and power are comparable with results of blade element methods that are largely used in the design of marine current turbines. The accuracy of numerical predictions tends to reduce in cases where turbine blades operate in off-design conditions.

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Experimental study of the turbulence intensity effects on marine current turbines behaviour. Part II: Two interacting turbines

Cited by 149 publications

References 11 publications

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

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

A wind‐tunnel study of the wake development behind wind turbines over sinusoidal hills

Marine Turbine Hydrodynamics by a Boundary Element Method with Viscous Flow Correction

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