An experimental investigation into non-linear wave loading on horizontal axis tidal turbines

Draycott, Samuel; Payne, Grégory S.; Steynor, Jeffrey; Nambiar, Anup; Sellar, Brian; Venugopal, Vengatesan

doi:10.1016/j.jfluidstructs.2018.11.004

Cited by 68 publications

(47 citation statements)

References 23 publications

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“…The gained amplitudes of all sub-data sets are average for each initial wave frequency f W . The results are verified with a single Fast Fourier transform (FFT) analysis [67], which showed a very good agreement.…”

Section: Heave Responsementioning

confidence: 66%

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Comparison of a Floating Cylinder with Solid and Water Ballast

Gabl

Davey

Nixon

et al. 2019

Water

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Modelling and understanding the motion of water filled floating objects is important for a wide range of applications including the behaviour of ships and floating platforms. Previous studies either investigated only small movements or applied a very specific (ship) geometry. The presented experiments are conducted using the simplified geometry of an open topped hollow cylinder ballasted to different displacements. Regular waves are used to excite the floating structure, which exhibits rotation angles of over 20 degrees and a heave motion double that of the wave amplitude. Four different drafts are investigated, each with two different ballast options: with (water) and without (solid) a free surface. The comparison shows a small difference in the body’s three translational motions as well as the rotation around the normal axis to the water surface. Significant differences are observed in the rotation about the wave direction comparable to parametric rolling as seen in ships. The three bigger drafts with free surface switch the dominant global rotation direction from pitch to roll, which can clearly be attributed to the sloshing of the internal water. The presented study provides a new dataset and comparison of varying ballast types on device motions, which may be used for future validation experiments.

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Section: Heave Responsementioning

confidence: 66%

“…The chosen approach is focused on an overall comparison. For a specific validation in the time-domain, the original measurement [1,2] should be checked for transient behaviour (especially switching between roll and pitch), and it is advisable to focus on the ramp up as well as the first stable oscillations [67].…”

Section: Minimum and Maximum Response Motionmentioning

confidence: 99%

Comparison of a Floating Cylinder with Solid and Water Ballast

Gabl

Davey

Nixon

et al. 2019

Water

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show abstract

“…Consequently, the decaying oscillation of the floating cylinder in the tank is not included. For a direct comparison of the results with a numerical simulation in the time domain, the provided time series can be reduced to the ramp-up time including the first stable oscillations [24]. This time period can be seen as nearly free floating based on the comparable soft mooring lines, and the influence of the reflections is small.…”

Section: Sum_ [Case Id] Txtmentioning

confidence: 99%

Experimental Data of a Floating Cylinder in a Wave Tank: Comparison Solid and Water Ballast

Gabl

Davey

Nixon

et al. 2019

Data

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The experimental set-up allows for the comparison of two different ballast options of a floating cylinder in a wave tank. Four different internal water drafts are tested as well as an equivalent solid ballast option. The model is excited by regular waves, which are characterised with five wave gauges in front of the floating cylinder and two behind. Additionally, the time series of the six-degree freedom response of the floating structure is made available. Regular waves with an initial amplitude of 0.05 m and frequencies over the range 0.3 to 1.1 Hz are investigated. This results in a wide range of different responses of the floating structure as well as very big rotations of up to 20 degrees. This dataset allows for identification of the influence caused by the sloshing of the interior water volume and can be used to validate numerical models of fluid–structure–fluid interaction.

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“…Understanding is required of the level (turbulence intensity) and nature (lengthscale) of both ambient turbulence (i.e. natural turbulence before TECs are installed and which will occur upstream of the TECs) and also turbulence post installation [21]. This influences the understanding of TEC wake formation and dissipation, interaction between TEC wakes in an array and fluctuations in load across a swept rotor area -informing TEC design to withstand fatigue and TEC siting within an array [22].…”

Section: The Industrymentioning

confidence: 99%