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Numerical methods are developed to simulate the wave propagation in heterogeneous 2D fluid / poroelastic media. Wave propagation is described by the usual acoustics equations (in the fluid medium) and by the low-frequency Biot's equations…

Classical Physics · Physics 2012-09-25 Guillaume Chiavassa , Bruno Lombard

We study the behavior of shallow water waves propagating over bathymetry that varies periodically in one direction and is constant in the other. Plane waves traveling along the constant direction are known to evolve into solitary waves, due…

Analysis of PDEs · Mathematics 2025-05-21 David I. Ketcheson , Giovanni Russo

In the linear approximation, we study a one-dimensional problem of the reflectionless wave propagation on a surface of a shallow duct with the spatially varying water depth, duct width, and current. We show that both global and bounded…

Fluid Dynamics · Physics 2021-12-08 Semyon Churilov , Yury Stepanyants

A one-way wave equation is an evolution equation in one of the space directions that describes (approximately) a wave field. The exact wave field is approximated in a high frequency, microlocal sense. Here we derive the pseudodifferential…

Analysis of PDEs · Mathematics 2007-05-23 Christiaan C. Stolk

In classical continuum physics, a wave is a mechanical disturbance. Whether the disturbance is stationary or traveling and whether it is caused by the motion of atoms and molecules or the vibration of a lattice structure, a wave can be…

Fluid Dynamics · Physics 2014-04-14 Ivan C. Christov

Several methods for handling sloping fluid-solid interfaces with the elastic parabolic equation are tested. A single-scattering approach that is modified for the fluid-solid case is accurate for some problems but breaks down when the…

Computational Physics · Physics 2020-05-22 Michael D. Collins , Adith Ramamurti

We investigate systems of degenerate parabolic equations idealizing reactive solute transport in porous media. Taking advantage of the inherent structure of the system that allows to deduce a scalar Generalized Porous Medium Equation for…

Analysis of PDEs · Mathematics 2014-12-19 Tuomo Kuusi , Léonard Monsaingeon , Juha Videman

In these last years, many studies have focalized on the design of reliable underwater acoustic communication systems. However, the ocean acoustic communication channel exhibits strong amplitude and phase fluctuations and the phenomena of…

Signal Processing · Electrical Eng. & Systems 2019-07-16 Yasin Yousif Al-Aboosi , Hussein A. Abdulnabi

Formulas are derived for solutions of many-body wave scattering problems by small particles in the case of acoustically soft, hard, and impedance particles embedded in an inhomogeneous medium. The limiting case is considered, when the size…

Mathematical Physics · Physics 2011-05-10 Alexander G. Ramm

The equations of motion in a macroscopically inhomogeneous porous medium saturated by a fluid are derived. As a first verification of the validity of these equations, a two-layer rigid frame porous system considered as one single porous…

A generalized kinetic model equation which takes into account the frequency depence of the thermal conductivity is used to analyze the problem of sound propagation in dilute polyatomic gases. By comparing the theoretical results with some…

Fluid Dynamics · Physics 2015-06-15 Sebastian Fischer , Wilson Marques

The stepwise coupled-mode model is a classic approach for solving range-dependent sound propagation problems. Existing coupled-mode programs have disadvantages such as high computational cost, weak adaptability to complex ocean environments…

Computational Physics · Physics 2023-03-14 Houwang Tu , Yongxian Wang , Chunmei Yang , Wei Liu , Wenbin Xiao , Xiaodong Wang

The paper derives and analyses the (semi-)discrete dispersion relation of the Parareal parallel-in-time integration method. It investigates Parareal's wave propagation characteristics with the aim to better understand what causes the well…

Numerical Analysis · Mathematics 2018-07-02 Daniel Ruprecht

An analogue of the geometrical optics for description of the modal structure of a wave field in a range-dependent waveguide is considered. In the scope of this approach the mode amplitude is expressed through solutions of the ray equations.…

Atmospheric and Oceanic Physics · Physics 2009-11-10 A. L. Virovlyansky , A. Yu. Kazarova , L. Ya. Lyubavin

In this paper the small-amplitude motion of multiple superposed viscous fluids is studied as a linearized initial-value problem. The analysis results in a closed set of equations for the Laplace transformed amplitudes of the interfaces that…

Fluid Dynamics · Physics 2019-04-24 Magnus Vartdal , Andreas Nygård Osnes

This study develops a theoretical framework for modeling acoustic pulse propagation in a non-ideal shallow-water waveguide. We derive an {\epsilon}-pseudodifferential operator ({\epsilon}-PDO) formulation from the general three-dimensional…

Mathematical Physics · Physics 2025-12-16 Aleksandr Kaplun , Boris Katsnelson

We consider the third-order wide-angle `parabolic' equation of underwater acoustics in a cylindrically symmetric fluid medium over a bottom of range-dependent bathymetry. It is known that the initial-boundary-value problem for this equation…

Numerical Analysis · Mathematics 2011-10-18 D. C. Antonopoulou , V. A. Dougalis , G. E. Zouraris

We consider a layer of an inviscid fluid with free surface which is subject to vertical high-frequency vibrations. We derive three asymptotic systems of equations that describe slowly evolving (in comparison with the vibration frequency)…

Fluid Dynamics · Physics 2017-11-22 Konstantin Ilin

We use Maxwell's equations in a sourceless, inhomogeneous medium with continuous permeability $\mu (\mathbf{r}) $ and permittivity $% \epsilon (\mathbf{r}) $ to study the wave propagation. The general form of the wave equation is derived…

General Physics · Physics 2013-09-17 S. Habib Mazharimousavi , Ashkan Roozbeh , M. Halilsoy

We generalize the invariant imbedding theory of the wave propagation and derive new invariant imbedding equations for the propagation of arbitrary number of coupled waves of any kind in arbitrarily-inhomogeneous stratified media, where the…

Optics · Physics 2009-11-10 Kihong Kim , Dong-Hun Lee , H. Lim