Modern methods for investigating the stability of a pitching floating platform wind turbine

Lennie, Matthew; Marten, David; Pechlivanoglou, George; Nayeri, Christian Navid; Paschereit, Christian Oliver

doi:10.5194/wes-2-671-2017

Cited by 6 publications

(5 citation statements)

References 12 publications

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“…The FVM‐based open source code QBlade was used to perform the numerical analysis in this study. FVM is the name of a simulation method family, but it refers particularly to the nonlinear lifting line method QBlade here.…”

Section: Modelled Wind Turbine and Numerical Methodsmentioning

confidence: 99%

On the power coefficient overshoot of an offshore floating wind turbine in surge oscillations

et al. 2018

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The Betz limit is widely accepted to be the upper limit for the power coefficient of open wind turbines. However, when investigating the power performance of an offshore floating wind turbine in surge oscillations, it is found that the Betz limit can be exceeded by the instantaneous power coefficient if the tip speed ratio is near the optimal tip speed ratio and the platform surge motion is severe enough. This exceeding phenomenon is defined as the power coefficient overshoot. Numerical simulations with the free vortex method show that the power coefficient overshoot is caused by the time lag between the power output and the wind farm power. The time lag and the resultant power coefficient overshoot intensify with the increasing plat-

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Section: Modelled Wind Turbine and Numerical Methodsmentioning

confidence: 99%

On the power coefficient overshoot of an offshore floating wind turbine in surge oscillations

et al. 2018

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“…Recently, models were presented, which can better predict the unsteady effects from the fore-aft motion of the rotor due to the floating platform motion. A first increase of complexity is the potential flow free-wake vortex method, which was used in [16,51,59,78], and [90]. An even higher fidelity can be expected from Computational Fluid Dynamics (CFD) simulations as done in [40,85], and [53].…”

Section: Floating Wind Turbine Dynamics and Modelingmentioning

confidence: 99%

Multibody modeling for concept-level floating offshore wind turbine design

Lemmer

Luhmann³

et al. 2020

Multibody Syst Dyn

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Existing Floating Offshore Wind Turbine (FOWT) platforms are usually designed using static or rigid-body models for the concept stage and, subsequently, sophisticated integrated aero-hydro-servo-elastic models, applicable for design certification. For the new technology of FOWTs, a comprehensive understanding of the system dynamics at the concept phase is crucial to save costs in later design phases. This requires low-and medium-fidelity models. The proposed modeling approach aims at representing no more than the relevant physical effects for the system dynamics. It consists, in its core, of a flexible multibody system. The applied Newton-Euler algorithm is independent of the multibody layout and avoids constraint equations. From the nonlinear model a linearized counterpart is derived. First, to be used for controller design and second, for an efficient calculation of the response to stochastic load spectra in the frequency-domain. From these spectra the fatigue damage is calculated with Dirlik's method and short-term extremes by assuming a normal distribution of the response. The set of degrees of freedom is reduced, with a response calculated only in the two-dimensional plane, in which the aligned wind and wave forces act. The aerodynamic model is a quasistatic actuator disk model. The hydrodynamic model includes a simplified radiation model, based on potential flow-derived added mass coefficients and nodal viscous drag coefficients with an approximate representation of the second-order slow-drift forces. The verification through a comparison of the nonlinear and the linearized model against a higher-fidelity model and experiments shows that even with the simplifications, the system response magnitude at the system eigenfrequencies and the forced response magnitude to wind and wave forces can be well predicted. One-hour simulations complete in about 25 seconds and even less in the case of the frequency-domain model. Hence, large sensitivity studies and even multidisciplinary optimizations for systems engineering approaches are possible.

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“…Extensive comparisons with experiments and other existing numerical tools are used to validate the relevance of QBlade predictions. 17,[22][23][24] Qblade models the 3D wake as a sheet of freely convected vortices, including trailing and realized vortices, behind the rotor. A bounded vortex and discretized panels are used to represent the blades.…”

Section: Methodsmentioning

confidence: 99%

Numerical investigation on the spanwise chord distribution effects on the performance of an H-darrieus vertical axis wind turbines

Souaissa,

Ghiss,

Bentaher

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part A:

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The efficiency of Darrieus wind turbines has increased significantly due to developments in blade design, albeit at the expense of the simplicity provided by simple straight blades. The purpose of this research is to gain insight into the influence of various curvatures embedded in the plan of the blade while maintaining its simple straight shape. A variation in chord length along the span defines the curvature. To assess their effect on performance and efficiency, concave, and convex Leading-Trailing Edged Blades (LTEB) are investigated and evaluated in comparison to straight blades. That is viable to gain valuable insight about these blade designs' potential advantages in various applications by studying their aerodynamic characteristics and flow characteristics. The Q-blade tool is used to simulate 3D unsteady Nonlinear Lifting Lines Free Vortex Wake (3D-NLLFVW). The virtual camber effect brought on by flow curvatures is implemented to improve the results' accuracy. According to the findings, H-Darrieus' aerodynamic efficiency climbed by 16% and 9.5% at high TSR. For the concave and convex LTEBs, the torque ripple is smoothed by 37% and 19%, respectively. Additionally, compared to the straight-bladed rotor, the chosen variations enable volume reductions of 53% and 28%.

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Modern methods for investigating the stability of a pitching floating platform wind turbine

Cited by 6 publications

References 12 publications

On the power coefficient overshoot of an offshore floating wind turbine in surge oscillations

On the power coefficient overshoot of an offshore floating wind turbine in surge oscillations

Multibody modeling for concept-level floating offshore wind turbine design

Numerical investigation on the spanwise chord distribution effects on the performance of an H-darrieus vertical axis wind turbines

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