Optimal Control for Wind Turbine Wake Mixing on Floating Platforms

Broek, Maarten J. van den; Berg, Daniel van den; Sanderse, Benjamin; Wingerden, Jan-Willem van

doi:10.1016/j.ifacol.2023.10.1165

Cited by 5 publications

(1 citation statement)

References 8 publications

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“…Other studies utilise the flexibility of the meshless formulation for the study of wind turbines on floating platforms. These consider, for example, the effects of platform motion on rotor induction (Sebastian and Lackner, 2012), unsteady aerodynamics in the near wake (Jeon et al, 2016), rotor performance on a moving platfrom (Dong et al, 2019), wake dynamics for specific motions (Lee and Lee, 2019), and control optimisation for a coupled aero-and hydrodynamic model (van den Broek et al, 2022c).…”

Section: Introductionmentioning

confidence: 99%

Free-vortex models for wind turbine wakes under yaw misalignment – a validation study on far-wake effects

Broek

Tavernier

Hulsman³

et al. 2023

Preprint

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Abstract. Near-wake effects of wind turbine models using the free-vortex wake have been extensively studied, but there is a lack of validation for such predictions in the mid to far wake. This paper presents a novel validation study using three free-vortex wake models of increasing complexity: an actuator disc, an actuator disc with rotation, and an actuator-line model. We emphasise the application for dynamic wind farm flow control optimisation with a focus on wake redirection using yaw misalignment. For that purpose, surrogate wake models should provide sufficiently accurate power predictions at low computational expense. Three sets of wind tunnel data are used for validation: flow measurements under steady yaw misalignment, time-resolved flow measurements for a step change in yaw, and turbine output measurements with yaw control and simulated wind direction variation. Results indicate that the actuator-disc model provides the best balance of computational cost and accuracy in power predictions for the mid to far wake, which is not significantly improved upon by the addition of rotation. In the near wake, the added complexity of the actuator-line model may provide value as it models blade loading and individual tip vortices. Altogether, this study conclusively demonstrates that the actuator-disc model is suitable for yaw control optimisation and provides important validation for further studies into optimisation of wake steering under time-varying conditions.

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Section: Introductionmentioning

confidence: 99%

Free-vortex models for wind turbine wakes under yaw misalignment – a validation study on far-wake effects

Broek

Tavernier

Hulsman³

et al. 2023

Preprint

View full text Add to dashboard Cite

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Wake dynamics of wind turbines in unsteady streamwise flow conditions

Wei,

El Makdah,

et al. 2024

J. Fluid Mech.

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The unsteady flow physics of wind-turbine wakes under dynamic forcing conditions are critical to the modelling and control of wind farms for optimal power density. Unsteady forcing in the streamwise direction may be generated by unsteady inflow conditions in the atmospheric boundary layer, dynamic induction control of the turbine or streamwise surge motions of a floating offshore wind turbine due to floating-platform oscillations. This study seeks to identify the dominant flow mechanisms in unsteady wakes forced by a periodic upstream inflow condition. A theoretical framework for the problem is derived, which describes travelling-wave undulations in the wake radius and streamwise velocity. These dynamics encourage the aggregation of tip vortices into large structures that are advected along in the wake. Flow measurements in the wake of a periodically surging turbine were obtained in an optically accessible towing-tank facility, with an average diameter-based Reynolds number of 300 000 and with surge-velocity amplitudes of up to 40 % of the mean inflow velocity. Qualitative agreement between trends in the measurements and model predictions is observed, supporting the validity of the theoretical analyses. The experiments also demonstrate large enhancements in the recovery of the wake relative to the steady-flow case, with wake-length reductions of up to 46.5 % and improvements in the available power at 10 diameters downstream of up to 15.7 %. These results provide fundamental insights into the dynamics of unsteady wakes and serve as additional evidence that unsteady fluid mechanics can be leveraged to increase the power density of wind farms.

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