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Boundary-layer transition measurements on Mach-scaled helicopter roter blades in climb

Weiss, Armin and Gardner, Anthony and Klein, Christian and Raffel, Markus (2017) Boundary-layer transition measurements on Mach-scaled helicopter roter blades in climb. CEAS Aeronautical Journal, pp. 613-623. Springer. DOI: 10.1007/sl3272-017-0263-2 ISSN 1869-5590

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Official URL: http://link.springer.com/article/10.1007/s13272-017-0263-2

Abstract

In this work laminar-turbulent boundary-layer transition is investigated on the suction side of Mach-scaled helicopter rotor blades in climb. The phenomenon is assessed by means of temperature-sensitive paint (TSP). Results are compared to a data sample acquired by infrared (IR) thermography and accompanied by integral thrust-and local surface pressure measurements at two radial blade sections. Spatially high resolved data allow for precise detection of boundary-layer transition along the outer 60 % of the blade span. Results obtained via TSP and IR show remarkable agreement with minor deviations due to different surface qualities of the respective blades tested. TSP data are obtained at various collective pitch angles and three different rotating speeds corresponding to chord Reynolds-and Mach numbers based on blade tip speed of Retip = 4.8-9.31x105 and Mtip = 0.29-0.57, respectively. The transition position is detected with an accuracy of better than 1% chord and the findings show overall coherence as blade loading and tip chord Reynolds number are varied. Experimental findings are shown tobe consistent with two-dimensional simulations using the eN-envelope method for transition prediction. Based on quantitative agreement between measured and calculated surface pressures, a comparison of the corresponding transition results suggests a critical amplification factor of Ncr. = 5.5 best suited for transition prediction in the rotating test facility of the DLR Göttingen.

Item URL in elib:https://elib.dlr.de/116938/
Document Type:Article
Additional Information:Volume 8, Issue 4; Published online: 19 September 2017
Title:Boundary-layer transition measurements on Mach-scaled helicopter roter blades in climb
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Weiss, ArminArmin.Weiss (at) dlr.dehttps://orcid.org/0000-0002-7532-2974
Gardner, Anthonyanthony.gardner (at) dlr.dehttps://orcid.org/0000-0002-1176-3447
Klein, ChristianChristian.Klein (at) dlr.deUNSPECIFIED
Raffel, MarkusMarkus.Raffel (at) dlr.deUNSPECIFIED
Date:2017
Journal or Publication Title:CEAS Aeronautical Journal
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:No
DOI :10.1007/sl3272-017-0263-2
Page Range:pp. 613-623
Publisher:Springer
ISSN:1869-5590
Status:Published
Keywords:boundary-layer transition, helicopter roter blades, temperature-sensitive paint, infrared thermography, eAN-method
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
Location: Göttingen
Institutes and Institutions:Institute for Aerodynamics and Flow Technology > Experimental Methods, GO
Institute for Aerodynamics and Flow Technology > Helicopter, GO
Deposited By: Bachmann, Barbara
Deposited On:13 Dec 2017 14:37
Last Modified:31 Jul 2019 20:14

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