An aeroacoustic wind tunnel test was conducted using a scaled isolated tiltrotor model consisting of a single rotor and nacelle. Acoustic data were acquired using an in-flow microphone wing traversed beneath the model to map the directivity of the near-field acoustic radiation of the rotor for a parametric variation of rotor angle-of-attack, tunnel speed, and rotor thrust. Acoustic metrics were examined to show trends of impulsive noise for the parametric variations. BVISPL maximum noise levels were found to increase with angle-of-attack (alpha) for constant advance ratio (mikro) and thrust coefficient (CT), although the maximum BVI levels were found at much higher alpha than for a typical helicopter. BVISPL levels were found to increase with mikro for constant alpha and CT. BVISPL was found to decrease with increasing CT for constant alpha and mikro, although BVISPL increased with thrust for a constant wake geometry. Acoustic metrics were also scaled for Mtip to show simple power law scaling could be used to correct acoustic metrics for small Mtip excursions.
Acoustic characteristics of an isolated tiltrotor model in the DNW
Die im DNW (Deutsch-Niederländischer Windkanal) gemessenen akustischen Eigenschaften eines isolierten Schwenkrotormodells
Journal of the American Helicopter Society ; 46 , 1 ; 72-80
2001
9 Seiten, 15 Bilder, 14 Quellen
Article (Journal)
English
Rotor (Drehflügel) , akustische Eigenschaft , Windkanal , Schallmessung , Versuchsmodell , Einlaufströmung , Mikrophon , Richtungsabhängigkeit , parametrische Anregung , Anstellwinkel (Tragflügel) , Strömungsgeschwindigkeit , Schub (Antrieb) , Schalldruck , Stoßlast , Hubschrauber , Wirbelströmung , Aeroakustik
Acoustic Characteristics of an Isolated Tiltrotor Model in the DNW
Online Contents | 2001
|XV-15 Tiltrotor Aircraft: 1997 Acoustic Testing
NTRS | 2003
|XV-15 Tiltrotor Aircraft: 1997 Acoustic Testing
NTIS | 2003
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