ON THE CONTRIBUTION FROM SKIN STEPS TO BOUNDARY-LAYER GENERATED INTERIOR NOISE
✍ Scribed by M.S. Howe
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 231 KB
- Volume
- 209
- Category
- Article
- ISSN
- 0022-460X
No coin nor oath required. For personal study only.
✦ Synopsis
An estimate is made of the aircraft interior noise produced by high subsonic turbulent wall pressures interacting with a fuselage skin step formed when adjacent, elastic panels overlap. The panels are modelled as thin elastic plates bonded in the vicinity of the step, and clamped along a line transverse to the mean flow direction. Sound is produced by scattering of the turbulence induced flexural skin motions at the clamp line, and by interaction of the turbulence pressure with the step. The skin step component is found to be significant at high frequencies, above the convective resonance frequency of the panels (at which the turbulence convection velocity equals the flexural wave speed). At typical cruise Mach numbers, however, when boundary layer generated sound is believed to dominate interior cabin noise, the critical frequency above which skin step noise is important is of the order of 10 kHz, which is beyond the range of interest in practice. The critical frequency is much lower at take-off and landing approach conditions, but the turbulent boundary layer is then a relatively unimportant contributor to cabin noise.