Sound radiation of a line source moving above an absorbing plane with a frequency-dependent admittance

This paper is concerned with the derivation of an analytical solution for the acoustic pressure field generated by a line source moving at a constant speed and height above an absorbing plane and summarizes the results obtained in a recent article [Dragna and Blanc-Benon, J. Sound Vib. 349, 259-275,...

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Bibliographic Details
Published in:The Journal of the Acoustical Society of America 2017-05, Vol.141 (5), p.3808-3808
Main Authors: Dragna, Didier, Blanc-Benon, Philippe
Format: Article
Language:English
Online Access:Get full text
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Summary:This paper is concerned with the derivation of an analytical solution for the acoustic pressure field generated by a line source moving at a constant speed and height above an absorbing plane and summarizes the results obtained in a recent article [Dragna and Blanc-Benon, J. Sound Vib. 349, 259-275, 2015]. As an extension of previous studies, the frequency dependence of the admittance is accounted for. First, a Lorentz transformation is used to obtain an equivalent stationary problem. A special attention is paid to the translation of the admittance boundary condition in the Lorentz space. An analytical solution is obtained as a Fourier transform. Excitation of surface waves is investigated depending on the Mach number. In the far field, an asymptotic expression is sought using the modified saddle point method. The solution is expressed under the form of a Weyl-Van der Pol formula, in which the admittance is evaluated at the Doppler frequency. Comparison of the pressure field obtained with the analytical solution and with a direct numerical simulation is performed. Finally, a parametric study is carried out showing that the frequency variations of the admittance must be accounted for if the source is located close to the ground and if its Mach number is greater than 0.2. [This work was supported by the LabEx Centre Lyonnais d’Acoustique of Universit\'e de Lyon, operated by the French National Research Agency (ANR-10-LABX-0060/ANR-11-IDEX-0007.]
ISSN:0001-4966
1520-8524
DOI:10.1121/1.4988417