Aerodynamic measurements on wind turbines

Schepers, J.G.; Schreck, S.

doi:10.1002/wene.320

Cited by 22 publications

(15 citation statements)

References 82 publications

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“…The relevance of improved modelling of the dynamic inflow effect can be seen in the recent development of new dynamic inflow models by Yu et al (2019), Madsen et al (2020) and Ferreira et al (2021). Schepers and Schreck (2018) emphasise the value of experimental investigations of aerodynamic effects and also specifically the dynamic inflow effect to further improve and validate models. Higher-fidelity simulations depend on calibration and thus cannot solely fill this gap.…”

Section: Introductionmentioning

confidence: 99%

Experimental analysis of radially resolved dynamic inflow effects due to pitch steps

et al. 2021

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Abstract. The dynamic inflow effect denotes the unsteady aerodynamic response to fast changes in rotor loading due to a gradual adaption of the wake. This does lead to load overshoots. The objective of the paper was to increase the understanding of that effect based on pitch step experiments on a 1.8 m diameter model wind turbine, which are performed in the large open jet wind tunnel of ForWind – University of Oldenburg. The flow in the rotor plane is measured with a 2D laser Doppler anemometer, and the dynamic wake induction factor transients in axial and tangential direction are extracted. Further, integral load measurements with strain gauges and hot-wire measurements in the near and close far wake are performed. The results show a clear gradual decay of the axial induction factors after a pitch step, giving the first direct experimental evidence of dynamic inflow due to pitch steps. Two engineering models are fitted to the induction factor transients to further investigate the relevant time constants of the dynamic inflow process. The radial dependency of the axial induction time constants as well as the dependency on the pitch direction is discussed. It is confirmed that the nature of the dynamic inflow decay is better described by two rather than only one time constant. The dynamic changes in wake radius are connected to the radial dependency of the axial induction transients. In conclusion, the comparative discussion of inductions, wake deployment and loads facilitate an improved physical understanding of the dynamic inflow process for wind turbines. Furthermore, these measurements provide a new detailed validation case for dynamic inflow models and other types of simulations.

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Section: Introductionmentioning

confidence: 99%

Experimental analysis of radially resolved dynamic inflow effects due to pitch steps

et al. 2021

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“…As the wind energy industry is maturing and wind turbines are growing, there is an increasing need for cost-effective monitoring and data analysis solutions to understand the complex aerodynamic and acoustic behaviour of the flexible blades (Schepers and Schreck, 2019). The incoming flow transports turbulent structures of different scales spatially and temporally, yielding aerodynamic load fluctuations that are complex to simulate.…”

Section: Full-scale Aerodynamic Measurementsmentioning

confidence: 99%

Development of a wireless, non-intrusive, MEMS-based pressure and acoustic measurement system for large-scale operating wind turbine blades

Barber¹,

Deparday²,

Marykovskiy³

et al. 2022

Preprint

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Abstract. As the wind energy industry is maturing and wind turbines are growing, there is an increasing need for cost-effective monitoring and data analysis solutions to understand the complex aerodynamic and acoustic behaviour of the flexible blades. Published measurements on operating rotor blades in real conditions are very scarce, due to the complexity of the installation and use of measurement systems. However, recent developments in electronics, wireless communication and MEMS sensors are making it possible to acquire data in a cost-effective and energy-efficient way. In this work, therefore, a cost-effective MEMS-based aerodynamic and acoustic wireless measurement system that is thin, non-intrusive, easy to install, low power, and self-sustaining is designed and tested. The results show that the system is capable of delivering relevant results continuously, although work needs to be done on calibrating and correcting the pressure signals, as well as on refining the concept for the attachment sleeve for weather protection in the field. Finally, two methods for using the measurements to provide added value to the wind energy industry are developed and demonstrated: (1) inferring local angle of attack via stagnation point detection using differential pressure sensors near the leading edge, and (2) detecting and classifying leading edge erosion using instantaneous snapshots of the measured pressure fields. On-going work involves field tests on an operating 6 kW wind turbine in Switzerland.

show abstract

“…The relevance of improved modelling of the dynamic inflow effect can be seen in the recent development of new dynamic inflow models by Yu et al (2019), Madsen et al (2020) and Ferreira et al (2021). Schepers and Schreck (2018) emphasise on the value of experimental investigations of aerodynamic effects and also specifically the dynamic inflow effect to further improve and validate models. Higher fidelity simulations depend on calibration and thus cannot solely fill this gap.…”

Section: Introductionmentioning

confidence: 99%

“…Higher fidelity simulations depend on calibration and thus cannot solely fill this gap. Further, Schepers and Schreck (2018) outline the importance of radius resolved aerodynamic measurements over integrated blade and rotor loads. No experimental investigation is available until now, where the wake induction is directly probed at various blade radii in the rotor plane.…”

Section: Introductionmentioning

confidence: 99%

Experimental analysis of radially resolved dynamic inflow effects due to pitch steps

Berger

Onnen

Schepers

et al. 2021

Preprint

View full text Add to dashboard Cite

Abstract. The dynamic inflow effect denotes the unsteady aerodynamic response to fast changes in rotor loading due to a gradual adaption of the wake. This does lead to load overshoots. The objective of the paper was to increase the understanding of that effect based on pitch step experiments on a 1.8 m diameter model wind turbine, which we performed in the large open jet wind tunnel of ForWind – University of Oldenburg. We measured the flow in the rotor plane with a 2D Laser Doppler Anemometer and were able to extract the dynamic wake induction factor transients in axial and tangential direction. Further, integral load measurements with strain gauges and hot wire measurements in the near and close far wake were performed. Our results show a clear gradual decay of the axial induction factors after a pitch step, giving the first direct experimental evidence of dynamic inflow due to pitch steps. We fitted two engineering models to the induction factor transients to further investigate the relevant time constants of the dynamic inflow process.We discussed the radial dependency of the axial induction time constants as well as the dependency on the pitch direction. We confirmed that the nature of the dynamic inflow decay is better described by two rather than only one time constant. The dynamic changes in wake radius were connected to the radial dependency of the axial induction transients. In conclusion, the comparative discussion of inductions, wake deployment and loads facilitated the improved physical understanding of the dynamic inflow process for wind turbines. Furthermore, these measurements provide a new detailed validation case for dynamic inflow models and other types of simulations.

show abstract

Aerodynamic measurements on wind turbines

Cited by 22 publications

References 82 publications

Experimental analysis of radially resolved dynamic inflow effects due to pitch steps

Experimental analysis of radially resolved dynamic inflow effects due to pitch steps

Development of a wireless, non-intrusive, MEMS-based pressure and acoustic measurement system for large-scale operating wind turbine blades

Experimental analysis of radially resolved dynamic inflow effects due to pitch steps

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