Using The Helix Mixing Approach On Floating Offshore Wind Turbines

Berg, Daniël van den; Tavernier, Delphine De; Wingerden, Jan‐Willem van

doi:10.1088/1742-6596/2265/4/042011

Cited by 8 publications

(6 citation statements)

References 17 publications

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“…In this case, the second turbine operated at its static optimum. The effect of the helix approach when applied to a floating wind turbine was investigated by van den Berg, de Tavernier & van Wingerden (2022). They observed that the helix incites significant yawing of the turbine, further aiding the wake recovery process.…”

Section: Introductionmentioning

confidence: 99%

The characteristics of helically deflected wind turbine wakes

Korb¹,

Asmuth²,

Ivanell³

2023

J. Fluid Mech.

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The helix approach is a new individual pitch control method to mitigate wake effects of wind turbines. Its name is derived from the helical shape of the wake caused by a rotating radial force exerted by the turbine. While its potential to increase power production has been shown in previous studies, the physics of the helical wake are not well understood to date. Open questions include whether the increased momentum in the wake stems from an enhanced wake mixing or from the wake deflection. Furthermore, its application to a row of more than two turbines has not been examined before. We study this approach in depth from both an analytical and numerical perspective. We examine large-eddy simulations (LES) of the wake of a single turbine and find that the helix approach exhibits both higher entrainment and notable deflection. As for the application to a row of turbines, we show that the phase difference between two helical wakes is independent of ambient turbulence. Examination of LES of a row of three turbines shows that power gains greatly depend on the phase difference between the helices. We find a maximum increase in the total power of approximately 10 % at a phase difference of $270^\circ$ . However, we do not optimise the phase difference any further. In summary, we provide a set of analytical tools for the examination of helical wakes, show why the helix approach is able to increase power production, and provide a method to extend it to a wind farm.

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Section: Introductionmentioning

confidence: 99%

The characteristics of helically deflected wind turbine wakes

Korb¹,

Asmuth²,

Ivanell³

2023

J. Fluid Mech.

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“…Knowing the location of the breakdown provides insight into when the wake mixing process is triggered. QBlade has previously been used in [12,17,13] for a similar type of research. The settings described in [17] are also used in this work.…”

Section: Methodsmentioning

confidence: 99%

“…For example, the Helix wake mixing method applies a time-varying tilt and yaw moment to the turbine that typically is of such magnitude that the motions remain small. However, semi-submersible type floaters such as the TripleSpar [11] have an eigenfrequency in yaw motion for which the excitation frequency falls within the frequency range with which the Helix is typically applied [12,13]. For a typical blade pitch input used for the Helix wake mixing method the resulting yaw motion can reach between 5 to 10 degrees for these type of platforms.…”

Section: Introductionmentioning

confidence: 99%

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The Influence of Floating Turbine Dynamics on the Helix Wake Mixing Method

Van Den Berg,

De Tavernier,

Gutknecht

et al. 2024

J. Phys.: Conf. Ser.

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Wake mixing techniques like the Helix have shown to be effective at reducing the wake interaction between turbines, which improves wind farm power production. When these techniques are applied to a floating turbine it will excite movement. The type and magnitude of movement are dependent on floater dynamics. This work investigates four different floating turbines. Of these four turbines, two are optimised variants of the TripleSpar and Softwind platforms with enhanced yaw motion. The other two are the unaltered versions of these platforms. When the Helix is applied to all four floating turbines, the increased yaw motion of the optimised TripleSpar results in a reduction in windspeed whereas the optimised Softwind sees an increase in windspeed with increased yaw motion. From simulations using prescribed yaw motion at different phase offsets between blade pitch and yaw motion, we can conclude that this is the driving factor for this difference.

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“…Since FOWTs are newer, the understanding and modeling of their wake characteristics is still in development. However, initial studies indicate that the wakes behind FOWTs may dissipate faster compared to wakes behind fixed-bottom wind turbines [29,30]. This suggests a potential advantage of floating offshore wind farms: Since utility-scale fixed-bottom wind farms can lose 10-20% of their energy production per year due to wake interactions between turbines [31], for the same layout as a fixedbottom wind farm in similar wind conditions, a floating wind farm may be able to produce significantly more energy by naturally mitigating wake interactions.…”

Section: Introductionmentioning

confidence: 99%