Sound absorption with variable acoustic resistance means by oscillatory air pressure signal
US3972383A · kind A · utility
13Cited by
4References
6Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Aug 1, 1975 |
| Grant date | Aug 3, 1976 |
| Priority date | — |
| Expiry date | Aug 1, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/02836
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A system for varying the acoustic resistance of an acoustical lining disposed in a duct of an air propulsor comprises a nonlinear sound suppression liner having a porous facing sheet overlying a plurality of cells and means for impinging a predetermined oscillatory air pressure signal of 100-160 dB at an inaudible frequency on the facing sheet to vary the acoustic resistance of the facing sheet to make it optimum for a selected sound level and airflow condition in the duct.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.