Scattering by a Cavity-Backed Baffled Membrane
Abstract
A thin, tightly stretched membrane is set in an acoustically rigid infinite plane. Above the plane is an acoustic fluid. Below the plane is an acoustically rigid cavity also filled with an acoustic fluid. A wave propagating in the upper half space is incident on the plane. The wave is scattered in the usual way from the rigid part of the plane as a specularly reflected wave. However, the field scattered by the membrane coupled to the cavity is more complex since the membrane deflects and oscillates in response to the incident wave. The added coupling of the cavity to the membrane provides for the possibility of coalescing modes. This problem is analyzed for two types of incident waves, time harmonic, and pulse, under a light fluid loading assumption. The solution to the time harmonic problem is approximated using the method of matched asymptotic expansion. The solution obtained is uniformly valid in the frequency domain and reveals the nature of the coupling between the membrane and the cavity. Special consideration is given to the possible coalesing modes. The backscattered farfield amplitude is determined and results are illustrated for a specific example.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1987
- Accession Number
- ADA177223
Entities
People
- William P. Baker
Organizations
- Air Force Institute of Technology