Weiss, Armin and Braukmann, Johannes N. and Kaufmann, Kurt (2019) Experimental and Numerical Investigations of Unsteady Boundary-Layer Transition on a Dynamically Pitching Subscale Helicopter Rotor Blade. In: 19th ONERA-DLR Aerospace Symposium (ODAS 2019). ODAS 2019, 19th ONERA-DLR Aerospace Symposium, 3.-5. Juni 2019, Meudon, France.
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Abstract
The presented work tackles the lack of experimental investigations of unsteady boundary-layer transition on rotor blades at cyclic pitch actuation, which are important for accurate performance predictions, for instance for helicopters in forward flight. Unsteady boundary-layer transition positions were measured on the blade suction side of a four-bladed subscale rotor by means of the non-intrusive Differential Infrared Thermography (DIT), which does not require instrumented rotor blades. Experiments were conducted at rotation rates corresponding to Mach and Reynolds numbers at 75% rotor radius of M_75 = 0.11, 0.22 and Re_75=10*5 = 1.7, 3.5 and at varying cyclic blade pitch settings. The setup allowed to sample boundary-layer transition across the outer 55% of the rotor radius. The study is complemented by numerical simulations including boundary-layer transition modelling based on semi-empirical transition criteria. For the first time, the work successfully applies DIT to capture unsteady boundary-layer transition on the blade suction side on rotating blades. Promising results reveal a plausible development of detected boundary-layer transition positions over the pitch cycle, a reasonable comparison to experimental results obtained using the established sigma c_p method and noticeable agreement to numerical simulations.
Item URL in elib: | https://elib.dlr.de/127485/ | ||||||||||||
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Document Type: | Conference or Workshop Item (Speech) | ||||||||||||
Title: | Experimental and Numerical Investigations of Unsteady Boundary-Layer Transition on a Dynamically Pitching Subscale Helicopter Rotor Blade | ||||||||||||
Authors: |
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Date: | June 2019 | ||||||||||||
Journal or Publication Title: | 19th ONERA-DLR Aerospace Symposium (ODAS 2019) | ||||||||||||
Refereed publication: | Yes | ||||||||||||
Open Access: | Yes | ||||||||||||
Gold Open Access: | No | ||||||||||||
In SCOPUS: | No | ||||||||||||
In ISI Web of Science: | No | ||||||||||||
Status: | Published | ||||||||||||
Keywords: | unsteady boundary-layer transition, rotor blades, differential infrared thermography (DIT), numerical simulations, helicopter | ||||||||||||
Event Title: | ODAS 2019, 19th ONERA-DLR Aerospace Symposium | ||||||||||||
Event Location: | Meudon, France | ||||||||||||
Event Type: | international Conference | ||||||||||||
Event Dates: | 3.-5. Juni 2019 | ||||||||||||
Organizer: | DLR/ONERA | ||||||||||||
HGF - Research field: | Aeronautics, Space and Transport | ||||||||||||
HGF - Program: | Aeronautics | ||||||||||||
HGF - Program Themes: | rotorcraft | ||||||||||||
DLR - Research area: | Aeronautics | ||||||||||||
DLR - Program: | L RR - Rotorcraft Research | ||||||||||||
DLR - Research theme (Project): | L - The Virtual Aerodynamic Rotorcraft (old) | ||||||||||||
Location: | Göttingen | ||||||||||||
Institutes and Institutions: | Institute for Aerodynamics and Flow Technology > Helicopter, GO | ||||||||||||
Deposited By: | Winkels, Elisabeth | ||||||||||||
Deposited On: | 12 Jun 2019 12:12 | ||||||||||||
Last Modified: | 31 Jul 2019 20:25 |
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