Scattering by coupled resonating elements in air
| Autor: | Alvin Yung Boon Chong, Anton Krynkin, Olga Umnova, Shahram Taherzadeh, Keith Attenborough |
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| Přispěvatelé: | Acoustics Research Centre [University of Salford], University of Salford, Department of Design Development Environment and Materials, The Open University [Milton Keynes] (OU) |
| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Acoustics and Ultrasonics
Plane wave Shell (structure) FOS: Physical sciences built_and_human_env Helmholtz resonance 01 natural sciences Scattering Resonator 0103 physical sciences Cylinder Boundary value problem Sonic crystals 010306 general physics 010301 acoustics Mathematical Physics Physics other 46.70.De Bragg's law Mathematical Physics (math-ph) Condensed Matter Physics Band gaps PACS numbers: 43.20.+g Surfaces Coatings and Films Electronic Optical and Magnetic Materials Computational physics 43.20.Ks Elastic shell Wavelength 43.50.+y Physics - Optics energy Optics (physics.optics) |
| Zdroj: | Journal of Physics D: Applied Physics Journal of Physics D: Applied Physics, IOP Publishing, 2011, 44 (12), pp.125501. ⟨10.1088/0022-3727/44/12/125501⟩ |
| ISSN: | 1361-6463 0022-3727 |
| DOI: | 10.1088/0022-3727/44/12/125501⟩ |
| Popis: | Scattering by (a) a single composite scatterer consisting of a concentric arrangement of an outer N-slit rigid cylinder and an inner cylinder which is either rigid or in the form of a thin elastic shell and (b) by a finite periodic array of these scatterers in air has been investigated analytically and through laboratory experiments. The composite scatterer forms a system of coupled resonators and gives rise to multiple low-frequency resonances. The corresponding analytical model employs polar angle dependent boundary conditions on the surface of the N-slit cylinder. The solution inside the slits assumes plane waves. It is shown also that in the low-frequency range the N-slit rigid cylinder can be replaced by an equivalent fluid layer. Further approximations suggest a simple square root dependence of the resonant frequencies on the number of slits and this is confirmed by data. The observed resonant phenomena are associated with Helmholtz-like behaviour of the resonator for which the radius and width of the openings are much smaller than the wavelength. The problem of scattering by a finite periodic array of such coupled resonators in air is solved using multiple scattering techniques. The resulting model predicts band-gap effects resulting from the resonances of the individual composite scatterers below the first Bragg frequency. Predictions and data confirm that use of coupled resonators results in substantial insertion loss peaks related to the resonances within the concentric configuration. In addition, for both scattering problems experimental data, predictions of the analytical approach and predictions of the equivalent fluid layer approximations are compared in the low-frequency interval. |
| Databáze: | OpenAIRE |
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