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We derive a new hyperbolic model describing the propagation of internal waves in a stratified shallow water with a non-hydrostatic pressure distribution. The construction of the hyperbolic model is based on the use of additional…

Fluid Dynamics · Physics 2020-05-28 Alexander Chesnokov , Valery Liapidevskii

Following our recent work [New J. Phys. 10, 053011, (2008)], here we demonstrate that due to strong nonlocal effects additional boundary conditions are essential to characterize the reflection of electromagnetic waves by nonconnected wire…

Materials Science · Physics 2015-05-13 M. G. Silveirinha

This paper continues the systematic investigation of diffusive shear instabilities initiated in Part I of this series. In this work, we primarily focus on quantifying the impact of non-local mixing, which is not taken into account in Zahn's…

Solar and Stellar Astrophysics · Physics 2018-07-25 D. Gagnier , P. Garaud

In this paper we study the motion of an internal water wave and an internal wave in a porous medium. For these problems we establish that, if the free boundary and, in the case of the Euler equations, also the tangential velocity at the…

Analysis of PDEs · Mathematics 2022-05-10 Zhiyuan Geng , Rafael Granero-Belinchón

We consider the vibrations and waves in the atmosphere under the gravitation on the flat earth. The stratified density distribution of the back ground equilibrium is supposed to touch the vacuum at the finite height of the stratosphere. We…

Analysis of PDEs · Mathematics 2020-02-25 Tetu Makino

The modeling of gravitational wave ringdown has traditionally relied on linear perturbation theory, which mainly describes the late-time behavior of a perturbed black hole after a binary merger. However, the need for more accurate ringdown…

General Relativity and Quantum Cosmology · Physics 2026-04-03 Macarena Lagos

Extensive studies have investigated the transition mechanism of boundary layers initiated by a single primary instability. In a real-world scenario, however, multiple primary instabilities of different physical nature would coexist and…

Fluid Dynamics · Physics 2026-03-18 Xiao-Bai Li , Yifeng Chen , Chihyung Wen , Peixu Guo

We present a method for extracting gravitational radiation from a three-dimensional numerical relativity simulation and, using the extracted data, to provide outer boundary conditions. The method treats dynamical gravitational variables as…

Gravitational waves in the presence of a non-minimal curvature-matter coupling are analysed, both in the Newman-Penrose and perturbation theory formalisms. Considering a cosmological constant as a source, the non-minimally coupled…

General Relativity and Quantum Cosmology · Physics 2018-05-03 Orfeu Bertolami , Cláudio Gomes , Francisco S. N. Lobo

In nonlocal general relativity, linearized gravitational waves are damped as they propagate from the source to the receiver in the Minkowski vacuum. Nonlocal gravity is a generalization of Einstein's theory of gravitation in which…

General Relativity and Quantum Cosmology · Physics 2015-06-15 B. Mashhoon

Second-order tensor perturbations induced by primordial fluctuations play a crucial role in probing small-scale physics, but gauge dependence of their energy density has remained a fundamental challenge in cosmological perturbation theory.…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-10 Chen Yuan , Yizhou Lu , Zu-Cheng Chen , Lang Liu

We analyze the propagation of gravitational waves in a medium containing bounded subsystems ("molecules"), able to induce significant Macroscopic Gravity effects. We establish a precise constitutive relation between the average quadrupole…

General Relativity and Quantum Cosmology · Physics 2019-07-26 Giovanni Montani , Fabio Moretti

In this work, we investigate mathematical models for electromagnetic wave propagation in dispersive isotropic media. We emphasize the link between physical requirements and mathematical properties of the models. A particular attention is…

Analysis of PDEs · Mathematics 2017-03-16 Maxence Cassier , Patrick Joly , Maryna Kachanovska

We study the nonlinear modulation property of flexural-gravity waves on a water surface covered by a compressed ice sheet of given thickness and density in a basin of a constant depth. For weakly nonlinear perturbations, we derive the…

Fluid Dynamics · Physics 2022-08-10 Alexey V. Slunyaev , Yury A. Stepanyants

We report the experimental observation of a robust horizontal mean flow induced by internal gravity waves. A wave beam is forced at the lateral boundary of a tank filled with a linearly stratified fluid initially at rest. After a transient…

Fluid Dynamics · Physics 2012-09-03 Guilhem Bordes , Antoine Venaille , Sylvain Joubaud , Philippe Odier , Thierry Dauxois

We present a new kind of generator of internal waves which has been designed for three purposes. First, the oscillating boundary conditions force the fluid particles to travel in the preferred direction of the wave ray, hence reducing the…

Atmospheric and Oceanic Physics · Physics 2009-11-13 Louis Gostiaux , Henri Didelle , Stephane Mercier , Thierry Dauxois

In this paper, we investigate the boundary layer arising from the fast internal waves in the Boussinesq equations with the Brunt-Vais\"al\"a frequency of order $ \mathcal O(1/\varepsilon) $. For the homogeneous-in-height stratification,…

Analysis of PDEs · Mathematics 2024-01-01 Rupert Klein , Xin Liu

The derivation of a Moving Boundary Approximation or of the response of a coherent structure like a front, vortex or pulse to external forces and noise, is generally valid under two conditions: the existence of a separation of time scales…

Condensed Matter · Physics 2009-10-31 Ute Ebert , Wim van Saarloos

In this paper we study the linear wave equation on an $n$-dimensional spatial domain. We show that there is a boundary triplet associated to the undamped wave equation. This enables us to characterise all boundary conditions for which the…

Optimization and Control · Mathematics 2015-11-09 Mikael Kurula , Hans Zwart

We study linear damped and viscoelastic wave equations evolving on a bounded domain. For both models, we assume that waves are subject to an inhomogeneous Neumann boundary condition on a portion of the domain's boundary. The analysis of…

Analysis of PDEs · Mathematics 2024-10-15 Türker Özsarı , İdem Susuzlu