Guiding airborne sound through surface modes of a two-dimensional phononic crystal
Küçük Resim Yok
Tarih
2015
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Iop Publishing Ltd
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Existence and guiding properties of surface modes bound to the interface between a finite two-dimensional phononic crystal and the host medium are experimentally and numerically demonstrated. Surface modes can be observed on both (1 0) and (1 1) surfaces of a square phononic crystal of steel cylinders in air. Numerical investigations of band properties and simulations of mode excitation are carried out through the finite-element method. Excited by the far field of a speaker, existence of surface modes is investigated by recording the sound field in the vicinity of the respective crystal surfaces. Both surface bands of the square phononic crystal depart from bulk bands and extend into the band gap for sufficiently high filling fractions. While such a surface band can be obtained for considerably smaller scatterer radii for the (1 0) surface, significantly higher radii around 0.49 of the lattice constant are required to obtain propagating surface modes on the (1 1) surface. Persistence of the guided surface mode along the (1 0) surface, where it diminishes in a length scale of the lattice constant in the transverse direction is demonstrated. The modes of the (1 1) surface decay faster into the air in the transverse direction. Guided modes on both surfaces propagate in a beating manner where the beat length can be determined by the wave number of the mode.
Açıklama
Anahtar Kelimeler
phononic crystal, surface modes, finite-element method
Kaynak
Journal of Physics D-Applied Physics
WoS Q Değeri
Q1
Scopus Q Değeri
Q1
Cilt
48
Sayı
23
