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On the Effect of Rotational Forces on Rotor Blade Boundary-Layer Transition

Weiss, Armin and Gardner, Anthony D. and Schwermer, Till and Klein, Christian and Raffel, Markus (2019) On the Effect of Rotational Forces on Rotor Blade Boundary-Layer Transition. AIAA Journal, 57 (1), pp. 252-266. American Institute of Aeronautics and Astronautics (AIAA). doi: 10.2514/1.J057036. ISSN 0001-1452.

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Official URL: https://arc.aiaa.org/doi/10.2514/1.J057036


Laminar-turbulent boundary-layer transition is investigated on the suction side of Mach-scaled helicopter rotor blades in climb and analyzed in view of the effect of rotational forces. Transition positions are detected with temperature-sensitive paint and complemented by surface pressure measurements at two radial blade sections. The effect of rotational forces is investigated by systematic variation of the Rossby number from Ro = 4.76 to Ro = 6.95 at Re = 3.7 x 10^5 and M = 0.22. The findings do not show a significant effect on boundary-layer transition in the investigated parameter range and suggest predominantly two-dimensional flow behavior. The result is supported by subsequent validation with two-dimensional numerical tools. Based on quantitative agreement between measured and calculated surface pressures, measured transition positions are predicted to within ±4% chord if a critical amplification factor of N_{cr,MSES} = 5.6 is used in the coupled Euler/boundary-layer equation solver MSES for transition prediction in the rotor test facility of the DLR, German Aerospace Center in Göttingen, Germany. The measured transition onset positions are also correlated with integral growth rates, obtained from separate two-dimensional compressible boundary-layer computations and subsequent local linear stability analysis to get transition N factors of N_{cr} = 8.4 ± 0.5. Differences in N factors are discussed in view of the different approaches used. Overall, transition N-factor correlations are independent of relative chord Reynolds number and incompressible shape factor at the detected transition onset. The findings underline the capability of two-dimensional numerical techniques based on linear stability theory to model boundary-layer transition in the investigated parameter range.

Item URL in elib:https://elib.dlr.de/119088/
Document Type:Article
Title:On the Effect of Rotational Forces on Rotor Blade Boundary-Layer Transition
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Weiss, ArminUNSPECIFIEDhttps://orcid.org/0000-0002-7532-2974UNSPECIFIED
Gardner, Anthony D.UNSPECIFIEDhttps://orcid.org/0000-0002-1176-3447UNSPECIFIED
Schwermer, TillUNSPECIFIEDhttps://orcid.org/0000-0002-6918-4480UNSPECIFIED
Klein, ChristianUNSPECIFIEDhttps://orcid.org/0000-0001-7592-6922UNSPECIFIED
Raffel, MarkusUNSPECIFIEDhttps://orcid.org/0000-0002-3340-9115133716012
Date:January 2019
Journal or Publication Title:AIAA Journal
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In ISI Web of Science:Yes
Page Range:pp. 252-266
Publisher:American Institute of Aeronautics and Astronautics (AIAA)
Keywords:boundary-layer transition, rotational effect, rotating blades, temperature-sensitive paint
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
Institute for Aerodynamics and Flow Technology > Experimental Methods, GO
Deposited By: Winkels, Elisabeth
Deposited On:08 Jan 2019 02:47
Last Modified:31 Oct 2023 15:12

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