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We introduce a new approach to constructing analytic solutions of the linear PDEs describing elastodynamics. This approach is illustrated for the case of a homogeneous isotropic half-plane body satisfying arbitrary initial conditions and…

Analysis of PDEs · Mathematics 2010-10-15 A. S. Fokas , D. Yang

We lay down the foundations of particle dynamics in mechanical theories that satisfy the relativity principle and whose kinematics can be formulated employing reference frames of the type usually adopted in special relativity. Such…

General Relativity and Quantum Cosmology · Physics 2009-06-30 Sebastiano Sonego , Massimo Pin

We report the development of a new ray-tracing simulation tool having the potential of the full characterization of a radio link through the accurate study of the propagation path of the signal from the transmitting to the receiving…

Computational Physics · Physics 2007-05-23 C. Tannous , J. Nigrin

Wave propagation and acoustic scattering problems require vast computational resources to be solved accurately at high frequencies. Asymptotic methods can make this cost potentially frequency independent by explicitly extracting the…

Numerical Analysis · Mathematics 2018-01-16 Daan Huybrechs , Peter Opsomer

Intensity distributions of linear wave fields are, in the high frequency limit, often approximated in terms of flow or transport equations in phase space. Common techniques for solving the flow equations for both time dependent and…

Computational Physics · Physics 2015-06-04 David J. Chappell , Gregor Tanner

We generalize the `filtering spectrum' [1] to probe scales along different directions by spatial coarse-graining. This multi-dimensional filtering spectrum quantifies the spectral content of flows that are not necessarily homogeneous. From…

Fluid Dynamics · Physics 2023-10-20 Dongxiao Zhao , Hussein Aluie

In Part I of this study, we obtained the ray (group) velocity gradients and Hessians with respect to the ray locations, directions and the anisotropic model parameters, at nodal points along ray trajectories, considering general anisotropic…

Geophysics · Physics 2021-12-01 Igor Ravve , Zvi Koren

We introduce a new method which resolves the problem of regularity and compactness of entropy solutions for nonlinear degenerate parabolic equations under non-degeneracy conditions on the sphere. In particular, we address a problem of…

Analysis of PDEs · Mathematics 2023-09-06 Marko Erceg , Darko Mitrović

In this paper, we study the Helmholtz transmission eigenvalue problem for inhomogeneous anisotropic media with the index of refraction $n(x)\equiv 1$ in two and three dimension. Starting with a nonlinear fourth order formulation established…

Numerical Analysis · Mathematics 2023-04-26 Qing Liu , Tiexiang Li , Shuo Zhang

An isogeometric boundary element method for problems in elasticity is presented, which is based on an independent approximation for the geometry, traction and displacement field. This enables a flexible choice of refinement strategies,…

Numerical Analysis · Computer Science 2015-02-04 Benjamin Marussig , Jürgen Zechner , Gernot Beer , Thomas-Peter Fries

Numerical methods for solving the ideal magnetohydrodynamic (MHD) equations in more than one space dimension must either confront the challenge of controlling errors in the discrete divergence of the magnetic field, or else be faced with…

Numerical Analysis · Mathematics 2015-05-19 Christiane Helzel , James A. Rossmanith , Bertram Taetz

We consider the scattering of elastic waves by highly oscillating anisotropic periodic media with bounded support. Applying the two-scale homogenization, we first obtain a constant coefficient second-order partial differential elliptic…

Analysis of PDEs · Mathematics 2018-02-06 Yi-Hsuan Lin , Shixu Meng

In this paper, we propose a new trace finite element method for the {Laplace-Beltrami} eigenvalue problem. The method is proposed directly on a smooth manifold which is implicitly given by a level-set function and require high order…

Numerical Analysis · Mathematics 2022-01-17 Song Lu , Xianmin Xu

We explore anisotropic regularisation methods in the spirit of [Holler & Kunisch, 14]. Based on ground truth data, we propose a bilevel optimisation strategy to compute the optimal regularisation parameters of such a model for the…

Numerical Analysis · Mathematics 2016-02-04 Martin Benning , Carola-Bibiane Schönlieb , Tuomo Valkonen , Verner Vlačić

A new approach was recently introduced by the authors for constructing analytic solutions of the linear PDEs describing elastodynamics. Here, this approach is applied to the case of a homogeneous isotropic half-space body satisfying…

Analysis of PDEs · Mathematics 2010-10-15 A. S. Fokas , D. Yang

The radiative transport equation accurately describes light transport in participating media such as biological tissues, though analytic solutions are known only for simple geometries. We present a pseudospectral technique to efficiently…

Computational Physics · Physics 2019-03-19 Samuel Powell , Ben T. Cox , Simon R. Arridge

A new fully discrete linearized $H^1$-conforming Lagrange finite element method is proposed for solving the two-dimensional magneto-hydrodynamics equations based on a magnetic potential formulation. The proposed method yields numerical…

Numerical Analysis · Mathematics 2019-03-12 Buyang Li , Jilu Wang , Liwei Xu

To help reveal the complete picture of linear kinetic drift modes, four independent numerical approaches, based on integral equation, Euler initial value simulation, Euler matrix eigenvalue solution and Lagrangian particle simulation,…

Plasma Physics · Physics 2017-07-04 H. S. Xie , Y. Y. Li , Z. X. Lu , W. K. Ou , B. Li

We develop a model of an electrorheological fluid such that the fluid is considered as an anisotropic one with the viscosity depending on the second invariant of the rate of strain tensor, on the module of the vector of electric field…

Mathematical Physics · Physics 2007-05-23 R. H. W. Hoppe , W. G. Litvinov

In this article, we analyze a two-level finite element method for the equations of motion arising in the flow of 2D Oldroyd model with non-smooth initial data. It involves solving the non-linear problem on a coarse grid of mesh-size $H$ and…

Numerical Analysis · Mathematics 2012-11-26 Deepjyoti Goswami