Acoustic radiation impedance of rectangular pistons on prolate spheroids

2002 ◽  
Vol 111 (2) ◽  
pp. 867-874 ◽  
Author(s):  
Jeffrey E. Boisvert ◽  
A. L. Van Buren
Keyword(s):  
Acoustic Radiation ◽  
Radiation Impedance ◽  
Prolate Spheroids

Radiation Loading of a Cylindrical Source in a Fluid-Filled Cylindrical Cavity Embedded Within a Fluid-Saturated Poroelastic Medium

2002 ◽  
Vol 69 (5) ◽  
pp. 675-683 ◽  
Author(s):  
S. M. Hasheminejad ◽  
H. Hosseini
Keyword(s):  
Seismic Waves ◽  
Acoustic Radiation ◽  
Surrounding Medium ◽  
Practical Importance ◽  
Closed Form Solution ◽  
Form Solution ◽  
Radiation Impedance ◽  
Harmonic Field ◽  
Cylindrical Source ◽  
Water Saturated

Radiation loading on a vibrating structure is best described through its radiation impedance. In the present work the modal acoustic radiation impedance load on an infinitely long cylindrical source harmonically excited in circumferentially periodic (axially independent) spatial pattern, while positioned concentrically within a fluid cylinder, which is embedded in a fluid-saturated unbounded elastic porous medium, is computed. This configuration, which is a realistic idealization of an acoustic logging tool suspended in a fluid-filled borehole within a permeable surrounding formation (White, J. E., 1983, Underground Sound Application of Seismic Waves, Elsevier, Amsterdam, Fig. 5.29, p. 183), is of practical importance with a multitude of possible applications in seismo-acoustics and noise control engineering. The formulation utilizes the Biot phenomenological model to represent the behavior of the sound in the porous, fluid-saturated, macroscopically homogeneous and isotropic surrounding medium. Employing the appropriate wave-harmonic field expansions and the pertinent boundary conditions for the given boundary configuration, a closed-form solution in the form of an infinite series is developed and the resistive and reactive components of modal radiation impedances are determined. A numerical example for a cylindrical surface excited in vibrational modes of various order, immersed in a water-filled cavity which is embedded within a water-saturated Ridgefield sandstone environment, is presented and several limiting cases are examined. Effects of porosity, frame stiffness, source size, and the interface permeability condition on the impedance values are presented and discussed.

Acoustic radiation from arrays on coated prolate spheroids

2004 ◽  
Vol 116 (4) ◽  
pp. 2590-2590
Author(s):  
Jeffrey E. Boisvert ◽  
A. L. Van Buren
Keyword(s):  
Acoustic Radiation ◽  
Prolate Spheroids

scholarly journals Sound Radiation due to Modal Vibrations of a Spherical Source in an Acoustic Quarterspace

2004 ◽  
Vol 11 (5-6) ◽  
pp. 625-635 ◽  
Author(s):  
Seyyed M. Hasheminejad ◽  
Mahdi Azarpeyvand
Keyword(s):  
Acoustic Radiation ◽  
Classical Method ◽  
Spherical Wave ◽  
Closed Form Solution ◽  
Addition Theorem ◽  
Form Solution ◽  
Surface Velocity ◽  
Rigid Boundary ◽  
Radiation Impedance ◽  
Spherical Source

Radiation of sound from a spherical source, vibrating with an arbitrary, axisymmetric, time-harmonic surface velocity, while positioned within an acoustic quarterspace is analyzed in an exact manner. The formulation utilizes the appropriate wave field expansions along with the translational addition theorem for spherical wave functions in combination with the classical method of images to develop a closed-form solution in form of infinite series. The analytical results are illustrated with numerical examples in which the spherical source, vibrating in the pulsating (n= 0) and translational oscillating (n= 1) modes, is positioned near the rigid boundary of a water-filled quarterspace. Subsequently, the basic acoustic field quantities such as the modal acoustic radiation impedance load and the radiation intensity distribution are evaluated for representative values of the parameters characterizing the system.

The Mutual Impedance Analysis of a Broadband Dense Plane Array

2012 ◽  
Vol 443-444 ◽  
pp. 1019-1025
Author(s):  
Wang Sheng Liu ◽  
Ya An Li ◽  
Lin Cui ◽  
Ming Huan Wang
Keyword(s):  
Boundary Element Method ◽  
Sound Pressure ◽  
Acoustic Radiation ◽  
Impedance Analysis ◽  
Normal Velocity ◽  
Radiation Impedance ◽  
Acoustic Performance ◽  
Mutual Impedance ◽  
Element Array ◽  
Definition Of

Due to the mutual radiation impedance may influence acoustics performance of a broadband dense plane array seriously, the expression of mutual radiation impedance among the transducers is developed according to the definition of mutual radiation impedance based on BEM（Boundary Element Method）. BEM model is established for acoustic radiation of a broadband dense plane array with nine elements. Sound pressure distribution of the nine-element array is solved using SYSNOISE software. And mutual radiation impedances are calculated on the condition of knowing surface normal velocity. Acoustic performance of the nine-element array is analysed through mutual radiation impedance. The influence of mutual impedance on acoustics performance for nine-element array is verified by comparing with measured curve of transducer conductance. The results show that it is successful to calculate mutual impedance of the array and predict acoustics performance using BEM.

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