Investigation of the floating IEA wind 15‐MW RWT using vortex methods Part II: Wake impact on downstream turbines under turbulent inflow

Ramos‐García, Néstor; Horcas, Sergio González; Pegalajar‐Jurado, Antonio; Kontos, Stavros; Bredmose, Henrik

doi:10.1002/we.2738

Cited by 14 publications

(11 citation statements)

References 35 publications

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“…The surge and pitch motions cause a streamwise velocity perturbation in the wake induced by the changes in rotor thrust (Kleine et al, 2022;Fontanella et al, 2022b;Ramos-García et al, 2022b). For example, Figure 14 shows the streamwise 775 velocity for the along wind HWA at = 5.48 and = 0.9 .…”

Section: Hwa Results 770mentioning

confidence: 99%

On the characteristics of the wake of a wind turbine undergoing large motions caused by a floating structure: an insight based on experiments and multi-fidelity simulations from the OC6 Phase III Project

Cioni

Papi

Pagamonci

et al. 2023

Preprint

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Abstract. This study reports the results of the second round of analyses of the OC6 project Phase III. While the first round investigated rotor aerodynamic loading, here focus is given to the wake behavior of a floating wind turbine under large motion. Wind tunnel experimental data from the UNsteady Aerodynamics for FLOating Wind (UNAFLOW) project are compared with the results of simulations provided by participants with methods and codes of different levels of fidelity. The effect of platform motion both on the near and the far wake is investigated. More specifically, the behavior of tip vortices in the near wake is evaluated through multiple metrics, such as streamwise position, core radius, convection velocity, and circulation. Additionally, the onset of velocity oscillations in the far wake is analyzed because this can have a negative effect on stability and loading of downstream rotors. Results in the near wake for unsteady cases confirm that simulations and experiments tend to diverge from the expected linearized quasi-steady behavior when the rotor reduced frequency increases over 0.5. Additionally, differences across the simulations become significant, suggesting that further efforts are required to tune the currently available methodologies in order to correctly evaluate the aerodynamic response of a floating wind turbine in unsteady conditions. Regarding the far wake, it is seen that, in some conditions, numerical methods over-predict the impact of platform motion on the velocity fluctuations. Moreover, results suggest that, different from original expectations about a faster wake recovery in a floating wind turbine, the effect of platform motion on the far wake seems to be limited or even oriented to the generation of a wake less prone to dissipation.

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Section: Hwa Results 770mentioning

confidence: 99%

On the characteristics of the wake of a wind turbine undergoing large motions caused by a floating structure: an insight based on experiments and multi-fidelity simulations from the OC6 Phase III Project

Cioni

Papi

Pagamonci

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Specifically, the wake for cases with surge motion remains almost straight, but an alternating wind speed is found in the wake, where the wake is separated by regions with relatively higher and lower wind speeds. This accordion-like wake movement (Ramos-García et al 2022) is referred to as wake pulsing by Messmer et al (2023). In contrast, both sway and yaw motions induce obvious lateral wake motions, i.e.…”

Section: Instantaneous Wakementioning

confidence: 95%

“…This accordion-like wake movement (Ramos-García et al. 2022) is referred to as wake pulsing by Messmer et al. (2023).…”

Section: Wake Response To Rotor Motions In Uniform Inflowmentioning

confidence: 96%

“…Special influences of FOWT motion were initially identified in the near wake in studies focusing on unsteady blade aerodynamics (Sebastian & Lackner 2012;Farrugia, Sant & Micallef 2016;Tran & Kim 2016;Fontanella et al 2021), where the breakdown of the tip vortices was found to be accelerated by FOWT motions. At a floating wind farm level, the focus is shifted to the motion-induced wake evolution at a larger downstream distance, using numerical simulations (Lee & Lee 2019;Kopperstad, Kumar & Shoele 2020;Chen, Liang & Li 2022;Li et al 2022;Kleine et al 2022;Ramos-García et al 2022), wind tunnel experiments with wind turbine models (Rockel et al 2014(Rockel et al , 2017Bayati et al 2017;Fu et al 2019;Schliffke, Aubrun & Conan 2020;Feist, Sotiropoulos & Guala 2021;Belvasi et al 2022;Meng et al 2022b;Messmer et al 2023) and field measurement with a full-scale FOWT (Angelou, Mann & Dubreuil-Boisclair 2023). Despite variations in the environmental settings, turbine sizes and motion types, these studies achieve some consensus on the far wake evolution of a FOWT, which are synthesized in the following.…”

Section: Introductionmentioning

confidence: 99%

“…2022; Ramos-García et al. 2022), wind tunnel experiments with wind turbine models (Rockel et al. 2014, 2017; Bayati et al.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Resolvent-based motion-to-wake modelling of wind turbine wakes under dynamic rotor motion

Li,

Yang

2024

J. Fluid Mech.

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We propose a linearized deterministic model for predicting coherent structures in the wake of a floating offshore wind turbine subject to platform motions. The model's motion-to-wake predictive capability is achieved through two building blocks: a motion-to-forcing (M2F) part and a forcing-to-wake (F2W) part. The M2F model provides a unified framework to parameterize the effects of arbitrary floating wind turbine motions as unsteady loads of a fixed actuator disk, requiring only the radial distribution of the aerodynamics force coefficient on the blade as input. The F2W model is derived based on a bi-global resolvent model obtained from the linearized Navier–Stokes equations, using the time-averaged wake of a fixed wind turbine as input. In addition to its capability of predicting sensitive frequency ranges, the model excels linear stability analysis by providing spatial modes of the wake response in a motion-specific and phase-resolved manner. The model successfully predicts the wake pulsing mode induced by surge, as well as the similarity and difference of the wake meandering modes caused by sway and yaw. Large-eddy simulations under different inflow turbulence intensities (TIs) and length scales are further conducted to analyse the wake meandering triggered by the simultaneous excitation of free-stream turbulence and sway motion. The results show distinct frequency signatures for the wake dynamics induced by ambient turbulence and sway motion. The inflow TI is found to have a stabilizing effect on the wake, reducing the motion-induced wake responses. Such a stabilizing effect is captured satisfactorily with the proposed model, provided that the effective viscosity is calibrated properly using the data from the fixed turbine wake under the corresponding turbulent inflow.

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Wake Structures and Performance of Wind Turbine Rotor With Harmonic Surging Motions Under Laminar and Turbulent Inflows

Li,

Yu,

Sarlak

2024

Wind Energy

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This study presents a comprehensive numerical analysis of a full‐scale horizontal‐axis floating offshore wind turbine (FOWT) rotor subjected to harmonic surging motions under both laminar and turbulent inflow conditions. Utilizing high‐fidelity computational fluid dynamics (CFD) simulations, namely, large eddy simulation (LES) with actuator line model (ALM), this research investigates the rotor performance, wake characteristics, and wake structures of a surging FOWT in detail. The study delves into the influence of varying inflow turbulence intensities, surging settings, and their interplay on the aerodynamic performance and the wake aerodynamics of a FOWT rotor. The results show that, through employing the phase‐averaging technique, surge‐induced periodic coherent structures (SIPeCS) can be identified in the wake of all the surging cases studied, irrespective of the inflow conditions and the surging settings. Additionally, the findings show that the faster wake recovery observed in the surging cases is not caused by enhancing the instability‐induced turbulence level, a previously accepted hypothesis. Instead, the results indicate that it is due to the enhanced advection process resulting from the induction fields of SIPeCS that causes the wake to recover faster. The analysis of rotor performance shows that the time‐averaged rotor performances are affected by the intricate aerodynamics arising from the surging motions. With certain surging settings, the time‐averaged thrust and the time‐averaged power of a surging rotor are found to be simultaneously lower and higher compared with those of a fixed rotor. Furthermore, the study underscores the importance of considering both the magnitude of surging and the rate of surging simultaneously to fully characterize the hysteresis load on a surging rotor.

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Investigation of the floating IEA wind 15‐MW RWT using vortex methods Part II: Wake impact on downstream turbines under turbulent inflow

Cited by 14 publications

References 35 publications

On the characteristics of the wake of a wind turbine undergoing large motions caused by a floating structure: an insight based on experiments and multi-fidelity simulations from the OC6 Phase III Project

On the characteristics of the wake of a wind turbine undergoing large motions caused by a floating structure: an insight based on experiments and multi-fidelity simulations from the OC6 Phase III Project

Resolvent-based motion-to-wake modelling of wind turbine wakes under dynamic rotor motion

Wake Structures and Performance of Wind Turbine Rotor With Harmonic Surging Motions Under Laminar and Turbulent Inflows

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