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, 2019-06-03 - 2019-06-05, 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 Start Date: | 3 June 2019 | ||||||||||||||||
Event End Date: | 5 June 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: | 24 Apr 2024 20:31 |
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