Element solution of electromagnetic problems over a wide frequency range via the Pade approximation

1999-02-12
In electromagnetic wave propagation problems, it is usually necessary to calculate the field quantities over a wide band of frequencies. In this paper, we develop a computationally-efficient scheme, which combines the finite element method (FEM) with the Pade approximation procedure, to derive the power series expansion of the unknown solution vector in terms of the frequency. Explicit power series expressions of the matrix operator are obtained for boundary value problems that are defined, not only over bounded spatial domains, but also over unbounded domains truncated either by an absorbing boundary condition (ABC) or by a perfectly matched layer (PML). It is shown that the FEM matrix is always a polynomial function of the frequency variable, even with the ABC or PML mesh truncations. The coefficients of the power series expansion are obtained iteratively, and certain a priori estimates are derived for the radius of convergence of this series expansion. Finally, Pade approximants are utilized to extend the region of convergence of the power series, enabling us to cover the frequency band with a minimum number of LU decompositions. (C) 1999 Elsevier Science S.A. All rights reserved.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING

Suggestions

EXACT NUMERICAL-SOLUTIONS FOR RADIATIVE HEAT-TRANSFER IN CYLINDRICAL FURNACES
Selçuk, Nevin (1988-05-01)
Exact expressions for the distributions of the components of radiative flux density and the radiative energy source term in terms of wall and medium temperature distributions have been formulated for an emitting absorbing medium of constant properties bounded by black walls of a cylindrical enclosure. The accuracy of numerical solutions has been tested on an idealized enclosure for which exact analytical solution of the expressions is possible and shown to have six‐figure accuracy. The exact expressions hav...
MAGNETOHYDRODYNAMIC FLOW IN ELECTRODYNAMICALLY COUPLED RECTANGULAR DUCTS
Tezer, Münevver (Wiley, 1988-06-01)
In Sezgin1,2 the problems considered are the magnetohydrodynamic (MHD) flows in an electrodynamically conducting infinite channel and in a rectangular duct respectively, in the presence of an applied magnetic field. In the present paper we extend the solution procedure of these papers to two rectangular channels connected by a barrier which is partially conductor and partially insulator. The problem has been reduced to the solution of a pair of dual series equations and then to the solution of a Fredholm's ...
Exact and FDM solutions of 1D MHD flow between parallel electrically conducting and slipping plates
Arslan, Sinem; Tezer, Münevver (Springer Science and Business Media LLC, 2019-08-01)
In this study, the steady, laminar, and fully developed magnetohydrodynamic (MHD) flow is considered in a long channel along with the z-axis under an external magnetic field which is perpendicular to the channel axis. The fluid velocity u and the induced magnetic field b depend on the plane coordinates x and y on the cross-section of the channel. When the lateral channel walls are extended to infinity, the problem turns out to be MHD flow between two parallel plates (Hartmann flow). Now, the variations of u...
Performance Evaluation of the Numerical Flux Jacobians in Flow Solution and Aerodynamic Design Optimization
Ezertas, Alper; Eyi, Sinan (2010-07-16)
A direct sparse matrix solver is utilized for the flow solution and the analytical sensitivity analysis. The effects of the accuracy of the numerical Jacobians on the accuracy of sensitivity analysis and on the performance of the Newton's method flow solver are analyzed in detail. The gradient based aerodynamic design optimization is employed to demonstrate those effects.
Atmospheric iridium at the South Pole as a measure of the meteoritic component
Tuncel, Süleyman Gürdal (Springer Science and Business Media LLC, 1987-10)
The measurement of iridium (Ir) in atmospheric samples is important because it gives information on the short-term flux of extraterrestrial material without interference from fragmentation products from large bodies. Such information cannot be obtained from sediment samples, because sediment samples integrate over millions of years and include contributions of large bodies impacted in that time period. In addition to flux information, through the analysis of Ir in atmospheric samples we can also evaluate a ...
Citation Formats
M. Kuzuoğlu, “Element solution of electromagnetic problems over a wide frequency range via the Pade approximation,” COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING, pp. 263–277, 1999, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/46027.