Role of quasinormal modes in controlling the sound transmission loss of duct mufflers

Leader, J. Carl; Tong, Yuhui

doi:10.1109/icnf.2015.7288634

Cited by 4 publications

(5 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The term quasinormal mode (QNM) is often used to describe a natural resonant vibration of an intrinsically dissipative system. While the terminology may vary 2 , the idea is relevant to virtually all branches of physics (see [1][2][3][4]). The fundamental idea is that, while waves may leave the system, they may not enter the system.…”

Section: Introductionmentioning

confidence: 99%

“…The existence and nature of gravitational QNMs of the Kerr geometry on the negative imaginary axis (NIA) have been poorly understood for quite some time 3 . Early numerical studies lacked the accuracy necessary to study QNMs near the NIA [8,9], but general arguments suggested that QNMs might not exist on the NIA [9].…”

Section: Introductionmentioning

confidence: 99%

“…None of these 7 points are QNMs. 3 QNM on the NIA are better understood in anti-de Sitter spaces (see [6]). They are even known to play a role in the anti-de Sitter/conformal field theory correspondence [7].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Purely imaginary quasinormal modes of the Kerr geometry

Cook

Zalutskiy

2016

Class. Quantum Grav.

View full text Add to dashboard Cite

We present a method for determining the purely imaginary quasinormal modes of the Kerr geometry. Such modes have previously been explored, but we show that prior results are incorrect. The method we present, based on the theory of Heun polynomials, is very general and can be applied to a broad class of problems, making it potentially useful to all branches of physics. Furthermore, our application provides an example where the method of matched asymptotic expansions seems to have failed. A deeper understanding of why it fails in this case may provide useful insights for other situations.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Purely imaginary quasinormal modes of the Kerr geometry

Cook

Zalutskiy

2016

Class. Quantum Grav.

View full text Add to dashboard Cite

show abstract

“…This was inspired by the early work of Flax et al [6], where the sound scattering from submerged elastic bodies is affected by various kinds of interference between the resonance scattering at the eigenfrequencies of the vibration of the body and the rigid-body scattering. Recently, such approach has been used to explain the peaks and valleys in the transmission loss curve of an expansion chamber subject to an incident plane-wave in a 1D duct [7]. It was demonstrated that the characteristics (complex eignevalues and mode shape functions) of the frequency-dependent quasinormal modes of the expansion chamber [8] allow the correct expansion of the sound pressure in the chamber.…”

Section: Introductionmentioning

confidence: 99%

Modal analysis of the scattering coefficients of an open cavity in a waveguide

Tong

2017

Wave Motion

Self Cite

View full text Add to dashboard Cite

The characteristics of an acoustic scatterer are often described by scattering coefficients. The understanding of the mechanisms involved in the frequency dependent features of the coefficients has been a challenge task, owing to the complicated coupling between the waves in open space and the modes inside the finite scatterer. In this paper, a frequency-dependent modal description of the scattering coefficient is utilized to study the modal properties of the scatterer. The important role that eigenmodes play in defining the features of the scattering coefficients is revealed via an expansion of the coefficients by the eigenmodes. The results show the local extrema of the scattering coefficients can be attributed to the constructive/destructive interference of resonant and non-resonant modes. In particular, an approximated equation, which is equivalent to the standard Fano formula, is obtained to describe the sharp anti-symmetric Fano characteristics of the scattering coefficients. The special cases where scattering is dominated by a single resonance eigenmode, corresponding to the "resonance transmission", are also illustrated.

show abstract

“…Recent progress in modelling the sound scattering coefficients of open cavities due to an incident wave from a connected waveguide have demonstrated that the frequency-dependent eigensolutions of the effective Hamiltonian matrix of the sound field in the open cavity can be used to describe the coupling between the sound fields in the cavity and waveguides. [9][10][11] In this paper, the frequency-dependent eigenmodes is used to describe sound fields in the acoustically coupled open cavity and a semi-infinite space. The eigenvalue problem is developed at a given frequency for generating frequency-dependent eigenmodes and eigenvalues.…”

Section: Introductionmentioning

confidence: 99%