High-speed infrared thermography was applied for boundary-layer transition measurements on the upper side of helicopter rotors. The transition detection is based on the analysis of a single instantaneous thermal image of the rotating blade and allows the determination of both the locations of the onset and of the end of the transition region. Measurements were performed on a Mach-scaled BO105 model rotor for different rotation frequencies. The transition characteristics are presented and compared to two-dimensional numerical simulations, and the measurement scatter is discussed. Additional transition measurements were performed on the main rotors of the DLR research helicopters Eurocopter BO105 and EC135. The transition behavior of the EC135 rotor blade is presented for different cases, and the effect of the contamination of the rotor blade leading edge on the laminar flow is discussed.
Boundary-layer transition measurements on hovering helicopter rotors by infrared thermography
Bestimmung des laminar-turbulenten Übergangs in der Grenzschicht am Flügelblatt eines Hubschraubers mittels Infrarotthermographie
Experiments in Fluids ; 55 , 7 ; 1-13
2014
13 Seiten
Article (Journal)
English
Boundary Layer Transition Measurements on Hovering Helicopter Rotors by Infrared Thermography
British Library Conference Proceedings | 2014
|Unsteady Boundary Layer Transition Measurements by Differential Infrared Thermography
British Library Conference Proceedings | 2014
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