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BOUNDARY LAYER INDUCED NOISE IN AIRCRAFT, PART II: THE TRIMMED FLAT PLATE MODEL

โœ Scribed by W.R. Graham

Publisher
Elsevier Science
Year
1996
Tongue
English
Weight
546 KB
Volume
192
Category
Article
ISSN
0022-460X

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โœฆ Synopsis

The influence of the cabin interior treatment on boundary layer noise levels is known to be significant, and we thus extend the model of Part I [1] to include it. The extended model consists of the boundary layer excited flat plate, with its internal surface covered by two dissipative layers (representing insulation) and an elastic plate (the trim panel). By comparison with the bare plate, the trimmed plate has much higher modal damping, due to the ability of the insulation to absorb energy at the wavenumbers associated with resonant modes, and greatly reduced radiation efficiency, due to the insulation's attenuating effect on supersonic wavenumber disturbances. Most of the conclusions of Part I are essentially unaffected by this behavioural modification, but structural damping treatments are now expected to have a negligible effect on the sound radiated by the plate.

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