A high-order computation of landing-gear noise and comparisons with existing experimental data are presented in this paper. It is demonstrated that a multi-block structured grid combined with high-order finite difference schemes and a novel block-interface condition leads to reliable aeroacoustic solutions for such a highly complex geometry with a relatively small number of grid points. Both aerodynamic and acoustic results compare well with the existing wind tunnel measurement data provided by Airbus for the 1:2.5 scaled model of an A320 nose landing-gear at the free-stream Mach number of 0.23. Far-field noise predictions using a solid FW-H surface showed good agreement with the acoustic measurement for the two-wheel landing-gear configuration. The baseline grid with 3.5 million cells was suitable for mean aerodynamics and produced reasonable acoustic prediction from 200 Hz to 2 kHz. The refined grid with 15.7 million cells increases the highest resolved frequency in the far-field acoustic spectra to 4 kHz. The refined grid is shown to be sufficient for accurate prediction of OASPL within 2 dB of the experimental measurement. The Mach number effect was investigated by collapsing the PSD spectra with those computed in the low Mach simulation at M=0.18, and showed that the far-field acoustics scaled roughly with U6. The investigation of individual gear components suggests that the wheels emit most of the noise in general but the axle contributes significantly in the direction straight down to the ground (overhead direction from an observer). The axle noise, which is associated with strong vortex shedding from the axle top/bottom surfaces, may be potentially higher than the wheel noise in that particular direction.
Landing-gear noise prediction using high-order finite difference schemes
Journal of Sound and Vibration ; 332 , 14 ; 3517-3534
2013
18 Seiten, 29 Bilder, 1 Tabelle, 29 Quellen
Article (Journal)
English
Landing-gear noise prediction using high-order finite difference schemes
Online Contents | 2013
|Landing gear and cavity noise prediction
TIBKAT | 1976
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