Acoustic waves generated by a point source in a sloping fluid layer

1989 ◽  
Vol 85 (4) ◽  
pp. 1414-1426 ◽  
Author(s):  
Yih‐Hsing Pao ◽  
Franz Ziegler ◽  
Yi‐Sun Wang
Keyword(s):  
Point Source ◽  
Acoustic Waves ◽  
Fluid Layer

Acoustic waves: a finite difference film

1983 ◽  
Vol 20 (3) ◽  
pp. 506-508
Author(s):  
George McMechan ◽  
Bill Price
Keyword(s):  
Finite Difference ◽  
Point Source ◽  
Acoustic Waves ◽  
Time Frame ◽  
Two Dimensional ◽  
Acoustic Wave Equation ◽  
Dimensional Model ◽  
Varying Thickness ◽  
Finite Difference Solution ◽  
Circular Wavefront

A finite difference solution of the acoustic wave equation is an ideal basis for making movies since the computations naturally provide a series of frames at successive, discrete time increments. Each time frame contains a picture of the wave field present at that time. An example is illustrated in a short (~2.8 Min) 16 mm film that shows the dynamic response of a two-dimensional model to a point source. The model consists of a layer of varying thickness that overlies a half space. The film shows the point source expanding into a circular wavefront that is reflected, refracted, and diffracted by the model.

Acoustic waves generated by a laser point source in an isotropic cylinder

2004 ◽  
Vol 116 (2) ◽  
pp. 814-820 ◽  
Author(s):  
Yongdong Pan ◽  
Clément Rossignol ◽  
Bertrand Audoin
Keyword(s):  
Point Source ◽  
Acoustic Waves ◽  
Isotropic Cylinder

Scattering of acoustic waves from a point source over an impedance wedge

Wave Motion ◽  
2020 ◽  
Vol 93 ◽  
pp. 102472
Author(s):  
Mikhail A. Lyalinov ◽  
Svetlana V. Polyanskaya
Keyword(s):  
Point Source ◽  
Acoustic Waves ◽  
Impedance Wedge ◽  
Scattering Of Acoustic Waves

scholarly journals Multi-Level Genetic Algorithm (GA)-based Acoustic-Elastodynamic Imaging of Coupled Fluid-Solid Media to Detect an Underground Cavity

2021 ◽  
Author(s):  
Bruno Guidio ◽  
Paula Ribeiro ◽  
Boo Hyun Nam ◽  
Chanseok Jeong
Keyword(s):  
Genetic Algorithm ◽  
Acoustic Waves ◽  
Elastic Moduli ◽  
Fluid Layer ◽  
Dominant Frequency ◽  
Measured Signal ◽  
Dimensional System ◽  
Computational Domain ◽  
Absorbing Boundary ◽  
Multi Level

This work studies the feasibility of imaging a coupled fluid-solid system by using the elastodynamic and acoustic waves initiated from the top surface of a computational domain. We consider a one- dimensional system, where a fluid layer is surrounded by two solid layers. The bottom solid layer is truncated by using a wave-absorbing boundary condition (WABC). We measure the wave responses on a sensor located on the top surface, and the measured signal contains information about the underlying physical system. By using the measured wave responses, we identify the elastic moduli of the solid layers and the depths of the interfaces between the solid and fluid layers. We employ a multi-level Genetic Algorithm (GA) combined with a frequency-continuation scheme to invert for the values of sought-for parameters. The numerical results show that the following findings. First, the depths of solid-fluid interfaces and elastic moduli can be reconstructed by the presented method. Second, the frequency-continuation scheme improves the convergence of the estimated values of parameters toward their targeted values. Lastly, the minimizer using a frequency-continuation system that increases the signal’s dominant frequency in each GA level is as effective as the other that decreases the signal’s dominant frequency. If this work is extended to a 3D setting, it can be instrumental to finding unknown locations of fluid-filled voids in geological formations that can lead to ground instability and/or collapse (e.g., natural/anthropogenic sinkhole, urban cave-in subsidence, etc.).

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