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We consider the convected Helmholtz equation with a generalized Myers boundary condition (a boundary condition of the second-order) and characterize the set of physical parameters for which the problem is weakly well-posed. The model comes…

Analysis of PDEs · Mathematics 2025-06-26 Nabil Alami , Edward Lucyszyn , Raphaél Pain Dit Hermier , Anna Rozanova-Pierrat

Hybrid inverse problems are based on the interplay of two types of waves, in order to allow for imaging with both high resolution and high contrast. The inversion procedure often consists of two steps: first, internal measurements involving…

Analysis of PDEs · Mathematics 2022-10-14 Giovanni S. Alberti

This paper concerns the frequency domain problem of diffraction of a plane wave incident on an infinite right-angled wedge on which impedance (absorbing) boundary conditions are imposed. It is demonstrated that the exact…

Analysis of PDEs · Mathematics 2015-06-22 David P. Hewett , Aaron Morris

A design methodology and synthesis equations are described for lumped-element filter prototypes having low-pass, high-pass, band-pass, or band-stop characteristics with theoretically perfect input- and output-match at all frequencies. Such…

Instrumentation and Methods for Astrophysics · Physics 2010-08-23 Matthew A. Morgan , Tod A. Boyd

A new construction of an absorbing boundary condition for indefinite Helmholtz problems on unbounded domains is presented. This construction is based on a near-best uniform rational interpolant of the inverse square root function on the…

Numerical Analysis · Mathematics 2015-07-23 Vladimir Druskin , Stefan Güttel , Leonid Knizhnerman

Gutzwiller wavefunction is a physically well motivated trial wavefunction for describing correlated electron systems. In this work, a new approximation is introduced to facilitate evaluation of the expectation value of any operator within…

Strongly Correlated Electrons · Physics 2015-08-25 Jun Liu , Yongxin Yao , Cai-Zhuang Wang , Kai-Ming Ho

Here we build some effective boundary conditions to be used in numerical calculations in order to avoid the thin meshing usually required in problems involving Hartmann layers near a locally plane wall. Wall model are provided for both…

Fluid Dynamics · Physics 2020-06-15 Alban Pothérat , Joël Sommeria , René Moreau

Recently, reduced order modeling methods have been applied to solving inverse boundary value problems arising in frequency domain scattering theory. A key step in projection-based reduced order model methods is the use of a sesquilinear…

Analysis of PDEs · Mathematics 2025-11-07 Andreas Tataris , Alexander V. Mamonov

This paper is devoted to the efficient numerical solution of the Helmholtz equation in a two- or three-dimensional rectangular domain with an absorbing boundary condition (ABC). The Helmholtz problem is discretized by standard bilinear and…

Numerical Analysis · Computer Science 2019-10-24 Jari Toivanen , Monika Wolfmayr

This paper is concerned with resolvent estimates on the real axis for the Helmholtz equation posed in the exterior of a bounded obstacle with Dirichlet boundary conditions when the obstacle is trapping. There are two resolvent estimates for…

Analysis of PDEs · Mathematics 2019-12-04 Simon N. Chandler-Wilde , Euan A. Spence , Andrew Gibbs , Valery P. Smyshlyaev

Terahertz frequencies are an untapped resource for providing high-speed short-range communications. As a result, it is of interest to study the propagation characteristics of terahertz waves and to develop channel models. In previous work…

Signal Processing · Electrical Eng. & Systems 2022-10-17 Thanh Le , Ha Tran , Suresh Singh

We consider wave propagation problems over 2-dimensional domains with piecewise-linear boundaries, possibly including scatterers. We assume that the wave speed is constant, and that the initial conditions and forcing terms are radially…

Numerical Analysis · Mathematics 2025-03-14 Davide Pradovera , Monica Nonino , Ilaria Perugia

A challenging problem in solving the Boltzmann equation numerically is that the velocity space is approximated by a finite region. Therefore, most methods are based on a truncation technique and the computational cost is then very high if…

Analysis of PDEs · Mathematics 2013-06-14 Minh-Binh Tran

This paper is concerned with acoustic scattering from a sound-soft trapezoidal surface in two dimensions. The trapezoidal surface is supposed to consist of two horizontal half-lines pointing oppositely, and a single finite vertical line…

Numerical Analysis · Mathematics 2019-03-19 Wangtao Lu , Guanghui Hu

Time-dependent density functional theory is widely used to describe excitations of many-fermion systems. In its many applications, 3D coordinate-space representation is used, and infinite-domain calculations are limited to a finite volume…

Nuclear Theory · Physics 2016-05-11 B. Schuetrumpf , W. Nazarewicz , P. -G. Reinhard

The method of the fundamental solutions (MFS) is used to construct an approximate solution for a partial differential equation in a bounded domain. It is demonstrated by combining the fundamental solutions shifted to the points outside the…

Numerical Analysis · Mathematics 2020-09-30 Shin-Ichiro Ei , Hiroyuki Ochiai , Yoshitaro Tanaka

The aim of this study is to present a reliable combination of the differential transformation method (DTM) and Pad\'e approximants to make, for the first time, a semi-analytic analysis of the problem of free convection boundary-layer flow…

Numerical Analysis · Mathematics 2012-12-10 Haldun Alpaslan Peker , Galip Oturanc

Reconstructing a density of states or similar distribution from moments or continued fractions is an important problem in calculating the electronic and vibrational structure of defective or non-crystalline solids. For single bands a…

Strongly Correlated Electrons · Physics 2015-05-20 Roger Haydock , C. M. M. Nex

The boundary element method is an efficient algorithm for simulating acoustic propagation through homogeneous objects embedded in free space. The conditioning of the system matrix strongly depends on physical parameters such as density,…

Numerical Analysis · Mathematics 2021-12-07 Elwin van 't Wout , Seyyed R. Haqshenas , Pierre Gélat , Timo Betcke , Nader Saffari

The inverse problem of reconstructing a source term from boundary measurements, for the wave equation, is revisited. We propose a novel approach to recover the unknown source through measuring the wave fields after injecting small…

Analysis of PDEs · Mathematics 2021-12-03 Mourad Sini , Haibing Wang
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