Inflow Turbulence and Leading Edge Roughness Effects on Laminar-Turbulent Transition on NACA 63-418 Airfoil

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Abstract

The surface imperfections and the inflow turbulence in real operational conditions can cause significant deviations from the predicted wind turbine aerodynamic performance and energy yield. In this study, particular emphasis was placed on the effect of these parameters on the laminar-turbulent transition on wind turbine blades. For this purpose, the DAN-AERO wind tunnel measurements, with high frequency microphones flush mounted on the both suction and pressure sides of the NACA 63-418 airfoil profile, were used. Typical operating condition Reynolds numbers, turbulence grid and boundary layer control devices on the surface were implemented. The results indicate a high dependency of the transition process on these parameters. The analyses show that the critical height of the leading edge roughness (LER) is to be met in order to have a bypass transition to turbulent flow at the angle of attacks, where the stagnation point is upstream of the LER location. The transition location moves closer to the leading edge with increasing Reynolds number when the roughness height is smaller than the critical height. Inflow turbulence is observed to have a larger effect on the transition location than the predicted numerical results.
Original languageEnglish
Article number022005
Book seriesJournal of Physics: Conference Series
Volume1037
Issue number2
Number of pages8
ISSN1742-6596
DOIs
Publication statusPublished - 2018
EventThe Science of Making Torque from Wind 2018 - Politecnico di Milano (POLIMI), Milan, Italy
Duration: 20 Jun 201822 Jun 2018
Conference number: 7
http://www.torque2018.org/

Conference

ConferenceThe Science of Making Torque from Wind 2018
Number7
LocationPolitecnico di Milano (POLIMI)
CountryItaly
CityMilan
Period20/06/201822/06/2018
Internet address

Bibliographical note

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Cite this

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title = "Inflow Turbulence and Leading Edge Roughness Effects on Laminar-Turbulent Transition on NACA 63-418 Airfoil: Paper",
abstract = "The surface imperfections and the inflow turbulence in real operational conditions can cause significant deviations from the predicted wind turbine aerodynamic performance and energy yield. In this study, particular emphasis was placed on the effect of these parameters on the laminar-turbulent transition on wind turbine blades. For this purpose, the DAN-AERO wind tunnel measurements, with high frequency microphones flush mounted on the both suction and pressure sides of the NACA 63-418 airfoil profile, were used. Typical operating condition Reynolds numbers, turbulence grid and boundary layer control devices on the surface were implemented. The results indicate a high dependency of the transition process on these parameters. The analyses show that the critical height of the leading edge roughness (LER) is to be met in order to have a bypass transition to turbulent flow at the angle of attacks, where the stagnation point is upstream of the LER location. The transition location moves closer to the leading edge with increasing Reynolds number when the roughness height is smaller than the critical height. Inflow turbulence is observed to have a larger effect on the transition location than the predicted numerical results.",
author = "{\"O}z{\cc}akmak, {{\"O} S} and Madsen, {H A} and S{\o}rensen, {N N} and S{\o}rensen, {J N} and Andreas Fischer and C Bak",
note = "Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.",
year = "2018",
doi = "10.1088/1742-6596/1037/2/022005",
language = "English",
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T1 - Inflow Turbulence and Leading Edge Roughness Effects on Laminar-Turbulent Transition on NACA 63-418 Airfoil

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AU - Özçakmak, Ö S

AU - Madsen, H A

AU - Sørensen, N N

AU - Sørensen, J N

AU - Fischer, Andreas

AU - Bak, C

N1 - Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

PY - 2018

Y1 - 2018

N2 - The surface imperfections and the inflow turbulence in real operational conditions can cause significant deviations from the predicted wind turbine aerodynamic performance and energy yield. In this study, particular emphasis was placed on the effect of these parameters on the laminar-turbulent transition on wind turbine blades. For this purpose, the DAN-AERO wind tunnel measurements, with high frequency microphones flush mounted on the both suction and pressure sides of the NACA 63-418 airfoil profile, were used. Typical operating condition Reynolds numbers, turbulence grid and boundary layer control devices on the surface were implemented. The results indicate a high dependency of the transition process on these parameters. The analyses show that the critical height of the leading edge roughness (LER) is to be met in order to have a bypass transition to turbulent flow at the angle of attacks, where the stagnation point is upstream of the LER location. The transition location moves closer to the leading edge with increasing Reynolds number when the roughness height is smaller than the critical height. Inflow turbulence is observed to have a larger effect on the transition location than the predicted numerical results.

AB - The surface imperfections and the inflow turbulence in real operational conditions can cause significant deviations from the predicted wind turbine aerodynamic performance and energy yield. In this study, particular emphasis was placed on the effect of these parameters on the laminar-turbulent transition on wind turbine blades. For this purpose, the DAN-AERO wind tunnel measurements, with high frequency microphones flush mounted on the both suction and pressure sides of the NACA 63-418 airfoil profile, were used. Typical operating condition Reynolds numbers, turbulence grid and boundary layer control devices on the surface were implemented. The results indicate a high dependency of the transition process on these parameters. The analyses show that the critical height of the leading edge roughness (LER) is to be met in order to have a bypass transition to turbulent flow at the angle of attacks, where the stagnation point is upstream of the LER location. The transition location moves closer to the leading edge with increasing Reynolds number when the roughness height is smaller than the critical height. Inflow turbulence is observed to have a larger effect on the transition location than the predicted numerical results.

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