Free-Flight Investigation of Transition under Turbulent Conditions on a Laminar Wing Glove

Reeh, Andreas; Weismüller, Michael; Tropea, Cameron

doi:10.2514/6.2013-994

Cited by 10 publications

(9 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is completely different from wind tunnel measurements (cf. Figure ), as was emphasized by other authors . As the precise TI depends too strongly on the low‐frequency cut‐off, it may only be concluded that laminar states are not necessarily excluded.…”

Section: Sample Results From Measurementsmentioning

confidence: 66%

“…As a final remark, it has to be noted that it seems to be common practice for mutual TS‐wave detection in free‐flight experiments to filter out a certain range of frequencies (e.g. from 0.1 to 2 kHz) from the reported time series to increase the visibility of possible peaks.…”

Section: Discussionmentioning

confidence: 99%

“…Aerodynamic data such as lift and drag coefficients were mostly determined by wind‐tunnel testing, but only partial knowledge is available regarding how these profiles perform under realistic operational conditions. For aircraft, however, there is a long tradition of investigating the boundary layer state on wings during normal flight operation . Comparable research on wind turbine blades is quite rare.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Experimental detection of laminar‐turbulent transition on a rotating wind turbine blade in the free atmosphere

2016

View full text Add to dashboard Cite

This paper discusses the findings from a measurement campaign on a rotating wind turbine blade operating in the free atmosphere under realistic conditions. A total of 40 pressure sensors together with an array of 23 usable hot-film sensors (based on constant temperature anemometry) were used to study the behavior of the boundary layer within a specific zone on the suction side of a 30 m diameter wind turbine at different operational states. A set of several hundreds of data sequences were recorded. Some of them show that under certain circumstances, the flow may be regarded as not fully turbulent. Accompanying Computational Fluid Mechanics (CFD) simulations suggest the view that a classical transition scenario according to the growth of so-called Tollmien-Schlichting did not apply.

show abstract

Section: Sample Results From Measurementsmentioning

confidence: 66%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Experimental detection of laminar‐turbulent transition on a rotating wind turbine blade in the free atmosphere

2016

View full text Add to dashboard Cite

show abstract

“…We now describe shortly how this may be related to turbulent-laminar transition on wind turbine blades. It has to be noted, that much more detailed investigations have been performed in the upper atmosphere for small aircrafts [3,4]. Corresponding field experiments on wind turbines were reported in [5,25].…”

Section: Impact On Boundary Layer Transition On a Wind Turbine Bladementioning

confidence: 99%

“…In most cases turbulence is treated in context of loads, and frequency ranges higher than a few Hertz are generally considered to be of no importance. However, this high frequency turbulence plays a significant role in laminar-to-turbulent transition inside the boundary layer of blades for airplanes [3,4] and wind turbines [5,6]. Due to the much higher drag of turbulent parts thereon, this may give rise to much less efficiency of wind turbines (in terms of c P ) as desired and a proper choice of airfoils is crucial.…”

Section: Introductionmentioning

confidence: 99%

Measurements of high-frequency Atmospheric Turbulence and its Impact on the Boundary Layer of Wind Turbine Blades

Schaffarczyk¹,

Jeromin²

2018

Preprint

View full text Add to dashboard Cite

To gain insight into the differences between onshore and offshore atmospheric turbulence, pressure fluctuations were measured for offshore wind under different environmental conditions. A durable piezo-electric sensor was used to sample turbulent pressure data at 50 kHz. Offshore measurements were performed at 100 m height on Germany's FINO3 offshore platform in the German Bight together with additional meteorological data provided by Deutscher Wetterdienst (DWD). The statistical evaluation revealed that the stability state in the atmospheric boundary has a large impact on turbulent fluctuations. Therefore, we used higher statistical properties (described by so-called shape factors) to the stability state. Data was classified to be either within the unstable, neutral or stable stratification. We found that in case of stable stratification, the shape factor is mostly close to zero, indicating that a thermally stable environment produces closer-to Gaussian distributions. Non-Gaussian distributions were found in unstable and neutral boundary layer states and an occurrence probability was estimated. Possible impact on laminar-turbulent transition on the blade is discussed with application of so-called laminar airfoils on wind turbine blades. Use of a cut-off frequency to separate load and aerodynamic turbulence is proposed.

show abstract

Experiments

Schaffarczyk¹

2020

Green Energy and Technology

View full text Add to dashboard Cite

Free-Flight Investigation of Transition under Turbulent Conditions on a Laminar Wing Glove

Cited by 10 publications

References 22 publications

Experimental detection of laminar‐turbulent transition on a rotating wind turbine blade in the free atmosphere

Experimental detection of laminar‐turbulent transition on a rotating wind turbine blade in the free atmosphere

Measurements of high-frequency Atmospheric Turbulence and its Impact on the Boundary Layer of Wind Turbine Blades

Experiments

Contact Info

Product

Resources

About

Free-Flight Investigation of Transition under Turbulent Conditions on a Laminar Wing Glove

Cited by 10 publications

References 22 publications

Experimental detection of laminar‐turbulent transition on a rotating wind turbine blade in the free atmosphere

Experimental detection of laminar‐turbulent transition on a rotating wind turbine blade in the free atmosphere

Measurements of high-frequency Atmospheric&nbsp;Turbulence and its Impact on the Boundary Layer of&nbsp;Wind Turbine Blades

Experiments

Contact Info

Product

Resources

About

Measurements of high-frequency Atmospheric Turbulence and its Impact on the Boundary Layer of Wind Turbine Blades