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Investigation of Laminar-Turbulent Transition on a Rotating Wind-Turbine Blade of Multimegawatt Class with Thermography and Microphone Array

Reichstein, Torben and Schaffarczyk, Alois Peter and Dollinger, Christoph and Balaresque, Nicolas and Schülein, Erich and Jauch, Clemens and Fischer, Andreas (2019) Investigation of Laminar-Turbulent Transition on a Rotating Wind-Turbine Blade of Multimegawatt Class with Thermography and Microphone Array. Energies, 12 (11), p. 2102. Multidisciplinary Digital Publishing Institute (MDPI). doi: 10.3390/en12112102. ISSN 1996-1073.

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Official URL: https://www.mdpi.com/1996-1073/12/11/2102


Knowledge about laminar–turbulent transition on operating multi megawatt wind turbine (WT) blades needs sophisticated equipment like hot films or microphone arrays. Contrarily, thermographic pictures can easily be taken from the ground, and temperature differences indicate different states of the boundary layer. Accuracy, however, is still an open question, so that an aerodynamic glove, known from experimental research on airplanes, was used to classify the boundary-layer state of a 2 megawatt WT blade operating in the northern part of Schleswig-Holstein, Germany. State-of-the-art equipment for measuring static surface pressure was used for monitoring lift distribution. To distinguish the laminar and turbulent parts of the boundary layer (suction side only), 48 microphones were applied together with ground-based thermographic cameras from two teams. Additionally, an optical camera mounted on the hub was used to survey vibrations. During start-up (SU) (from 0 to 9 rpm), extended but irregularly shaped regions of a laminar-boundary layer were observed that had the same extension measured both with microphones and thermography. When an approximately constant rotor rotation (9 rpm corresponding to approximately 6 m/s wind speed) was achieved, flow transition was visible at the expected position of 40% chord length on the rotor blade, which was fouled with dense turbulent wedges, and an almost complete turbulent state on the glove was detected. In all observations, quantitative determination of flow-transition positions from thermography and microphones agreed well within their accuracy of less than 1%.

Item URL in elib:https://elib.dlr.de/127678/
Document Type:Article
Additional Information:EISSN 1996-1073
Title:Investigation of Laminar-Turbulent Transition on a Rotating Wind-Turbine Blade of Multimegawatt Class with Thermography and Microphone Array
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Reichstein, TorbenKiel University of Applied SciencesUNSPECIFIED
Schaffarczyk, Alois PeterKiel University of Applied Scienceshttps://orcid.org/0000-0002-9357-3232
Dollinger, ChristophUniversität Bremenhttps://orcid.org/0000-0002-0679-5073
Balaresque, NicolasDeutsche WindGuard Engineering GmbHUNSPECIFIED
Schülein, ErichErich.Schuelein (at) dlr.dehttps://orcid.org/0000-0002-1125-8504
Jauch, ClemensFlensburg University of Applied Scienceshttps://orcid.org/0000-0002-2024-4497
Fischer, AndreasUniversität Bremenhttps://orcid.org/0000-0001-7349-7722
Date:1 June 2019
Journal or Publication Title:Energies
Refereed publication:Yes
Open Access:Yes
Gold Open Access:Yes
In ISI Web of Science:Yes
DOI :10.3390/en12112102
Page Range:p. 2102
EditorsEmailEditor's ORCID iD
Publisher:Multidisciplinary Digital Publishing Institute (MDPI)
Series Name:Wind, Wave and Tidal Energy
Keywords:boundary-layer transition; wind turbine; thermography; aerodynamic glove
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:fixed-wing aircraft
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Simulation and Validation (old)
Location: Göttingen
Institutes and Institutions:Institute for Aerodynamics and Flow Technology > High Speed Configurations, GO
Deposited By: Schülein, Dr.rer.nat. Erich
Deposited On:06 Jun 2019 15:43
Last Modified:14 Dec 2019 04:24

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