Geometrical acoustics

2014 ◽  
pp. 123-144
Keyword(s):  
Geometrical Acoustics

scholarly journals Computer Modeling of Barrel-Vaulted Sanctuary Exhibiting Flutter Echo with Comparison to Measurements

Acoustics ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 87-109
Author(s):  
Heather Lai ◽  
Brian Hamilton
Keyword(s):  
Computer Modeling ◽  
Architectural Design ◽  
Impulse Responses ◽  
Time Frequency ◽  
Geometrical Acoustics ◽  
Decay Times ◽  
Before And After ◽  
Show Evidence ◽  
Architectural Planning ◽  
The Cost

Computer modeling in acoustics allows for the prediction of acoustical defects and the evaluation of potential remediations. In this article, computer modeling is applied to the case of a barrel-vaulted sanctuary whose architectural design and construction led to severe flutter echoes along the main aisle, which was later mitigated through acoustical remediations. State-of-the-art geometrical acoustics and wave-based simulations are carried out to analyze the acoustics of this space, with a particular focus on the flutter echoes along the main aisle, before and after remediations. Multi-resolution wavelet and spectrogram analyses are carried out to isolate and characterize flutter echoes within measurements and computer-simulated room impulse responses. Comparisons of simulated responses to measurements are also made in terms of decay times and curves. Simulated room impulse responses from both geometrical acoustics and wave-based methods show evidence of flutter echoes matching measurements, to varying degrees. Time-frequency analyses isolating flutter echoes demonstrate better matches to measurements from wave-based simulated responses, at the cost of longer simulation times than geometrical acoustics simulations. This case study highlights the importance of computer modeling of acoustics in early design phases of architectural planning of worship spaces.

Geometrical Acoustics

1990 ◽  
pp. 46-57 ◽  
Author(s):  
Josef Krautkrämer ◽  
Herbert Krautkrämer
Keyword(s):  
Geometrical Acoustics

An approximate method in high-frequency scattering

1962 ◽  
Vol 58 (4) ◽  
pp. 662-670
Author(s):  
A. Sharples
Keyword(s):  
Boundary Condition ◽  
Circular Cylinder ◽  
Integral Representation ◽  
Sound Wave ◽  
High Frequency ◽  
Correction Term ◽  
Scattering Coefficient ◽  
Extended Form ◽  
Geometrical Acoustics ◽  
Plane Sound

ABSTRACTThe diffraction of a high-frequency plane sound wave by a circular cylinder is investigated when the boundary condition on the cylinder is expressed by means of an equation of the form The special feature of this investigation is that an extended form of the Kirchhoff-Fresnel theory of diffraction is used to find an integral representation for the scattering coefficient. In order to avoid the complicated analysis which would be necessary to evaluate the integrals concerned, the more natural geometrical acoustics approach is used to find the first correction term in the scattering coefficient. Numerical results are given for large and small values of the impedance Z.

scholarly journals PROPAGATION OF LOCALIZED VIBRATION MODES ALONG EDGES OF IMMERSED WEDGE-LIKE STRUCTURES: GEOMETRICAL-ACOUSTICS APPROACH

1999 ◽  
Vol 07 (01) ◽  
pp. 59-70 ◽  
Author(s):  
VICTOR V. KRYLOV
Keyword(s):  
Wave Propagation ◽  
Acoustic Waves ◽  
Nonlinear Function ◽  
Experimental Investigations ◽  
Elastic Plates ◽  
Liquid Loading ◽  
Geometrical Acoustics ◽  
Subsonic Regime ◽  
Supersonic Regime ◽  
Elastic Modes

The theory of antisymmetric localized elastic modes propagating along edges of immersed wedge-like structures is developed using the geometrical-acoustics approach to the description of flexural waves in elastic plates of variable thickness. The velocities of these modes, often called wedge acoustic waves, are calculated using solutions of the dispersion equation of the Bohr-Sommerfeld type following from the geometrical-acoustics description of localized wedge modes. In a subsonic regime of wave propagation, i.e. for wedge modes slower than sound in liquid, the influence of liquid loading results in significant decrease of wedge wave velocities in comparison with their values in vacuum. This decrease is a nonlinear function of a wedge apex angle θ and is more pronounced for small values of θ. In a supersonic regime of wedge wave propagation, a smaller decrease in velocities takes place and the waves travel with the attenuation due to radiation of sound into the surrounding liquid. The comparison is given with the recent experimental investigations of wedge waves carried out by independent researchers.

scholarly journals Prediction of jet mixing noise with Lighthill's Acoustic Analogy and geometrical acoustics

2017 ◽  
Vol 141 (2) ◽  
pp. 1203-1213 ◽  
Author(s):  
Carlos R. S. Ilário ◽  
Mahdi Azarpeyvand ◽  
Victor Rosa ◽  
Rod H. Self ◽  
Júlio R. Meneghini
Keyword(s):  
Acoustic Analogy ◽  
Jet Mixing ◽  
Geometrical Acoustics ◽  
Mixing Noise
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