Integral equation modeling of cylindrically periodic scatterers in the interior of a cylindrical waveguide

Anastassiu, H.T.; Volakis, John L.; Filipović, Dejan S.

doi:10.1109/22.734568

Cited by 19 publications

(15 citation statements)

References 12 publications

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“…In the context of the boundary element method, MDAs are developed for potential problems in [154,169], linear elasticity problems in [170,171] and electromagnetic problems in [132]. A MDA for an integral equation method for scattering from cylindrically periodic structures is proposed in [6].…”

Section: Mfs Mdamentioning

confidence: 99%

Matrix decomposition algorithms for elliptic boundary value problems: a survey

2010

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We provide an overview of matrix decomposition algorithms (MDAs) for the solution of systems of linear equations arising when various discretization techniques are applied in the numerical solution of certain separable elliptic boundary value problems in the unit square. An MDA is a direct method which reduces the algebraic problem to one of solving a set of independent one-dimensional problems which are generally banded, block tridiagonal, or almost block diagonal. Often, fast Fourier transforms (FFTs) can be employed in an MDA with a resulting computational cost of O(N 2 log N) on an N × N uniform partition of the unit square. To formulate MDAs, we require knowledge of the eigenvalues and eigenvectors of matrices arising in corresponding two-point boundary value problems in one space dimension. In many important cases, these eigensystems are known explicitly, while in others, they must be computed. The first MDAs were formulated almost fifty years ago, for finite difference methods. Herein, we discuss more recent developments in the formulation and application of MDAs in spline collocation, finite element Galerkin and spectral methods, and the method

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Section: Mfs Mdamentioning

confidence: 99%

Matrix decomposition algorithms for elliptic boundary value problems: a survey

2010

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“…2 Simplified jet engine inlet model design, fabrication and measurements The simplified inlet model was first adopted in [2], and further analysed in [3][4][5][6][7][8][9][10][11]. There are two basic versions of this model, one with straight blades, depicted in Fig.…”

Section: Introductionmentioning

confidence: 99%

Comparative study of miscellaneous methods applied to a benchmark, inlet scattering problem

Fromentin-Denozière¹,

Simon²,

Tzoulis³

et al. 2015

IET Radar, Sonar & Navigation

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Several well-known computational methods, based on various mathematical concepts, are applied to the electromagnetic scattering analysis of a benchmark cavity structure. Specifically, a simplified jet engine inlet configuration is defined, constructed and used as reference, whereas predicted numerical results for the radar cross-section are compared with measurements. The merits and drawbacks of each method are highlighted and quantified, with respect to accuracy, efficiency, resource requirements, reliability and robustness. Conclusions may be exploited in the near future in the construction of reliable classifiers, used in non-cooperative target identification

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“…Some of them combine high-frequency techniques in the empty part of the inlet with numerical methods in the loaded section [7][8][9][10][11][12]. Despite the advantages of these methods, they still require a large number of degrees of freedom, which makes them very difficult to apply to large structures.…”

Section: Introductionmentioning

confidence: 99%

Computation of radar cross section of jet engine inlets

Liu¹,

Dunn²,

Baldensperger³

et al. 2002

Micro & Optical Tech Letters

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COMPUTATION OF RADAR CROSS SECTION OF JET ENGINE INLETSJianKey words: radar cross sections; finite element method; numerical method INTRODUCTIONElectromagnetic scattering from jet engine inlets is an important topic of research due to the significant contribution that the inlet has to the radar cross section (RCS) of modern aircraft. Many researchers have studied this topic using an assortment of different methods. Some techniques applied to the problem are standard methods, such as mode matching (MM) [1, 2], shooting and bouncing ray (SBR) [3, 4], as well as the finite element method (FEM) and method of moment (MoM) techniques [5,6]. It is known, however, that these standard methods have some serious drawbacks that prevent them from being fully used to compute the RCS for practical jet engine inlets. In the case of MM, the resulting system demonstrates slow convergence and requires a large number of modes as well as a poorly conditioned large matrix to invert. Furthermore, rigorous modal methods are only useful for simple geometries that can have canonical terminations [2]. The problems with SBR techniques are that, while they are simple and efficient, they lack the required accuracy to handle arbitrary complex structures. Standard FEM and MoM have trouble handling the entire structure due to its large size.More recently, hybrid methods have been introduced to solve this important problem. Some of them combine high-frequency techniques in the empty part of the inlet with numerical methods in the loaded section [7][8][9][10][11][12]. Despite the advantages of these methods, they still require a large number of degrees of freedom, which makes them very difficult to apply to large structures. Some researchers reduce this domain for the case of simple periodic geometries, but for arbitrarily shaped inlets these methods are still limited by their memory and CPU time requirements.A particular method that is very well suited to the computation of RCS of jet engine inlets is the finite element-boundary integral (FE-BI) method [13,14]. Since jet engine inlets are complex geometries that may have complex material composition, this is well suited for a finite element approach. The domain size is truncated with a boundary integral, which reduces the overall simulation domain. Furthermore, the techniques described in [13] and [14] exploit the structure of the FE-BI equations to require minimal memory (only proportional to the maximum cross section of the inlet and independent of its depth) and computation time, which increases linearly with respect to the inlet depth.In both [13] and [14], the FE-BI method was applied to empty cavities. Although the calculated results were compared extensively with the results obtained using other techniques, little comparison was given with measured data. In this article, we extend the FE-BI method to inlets with complex internal structures and present results applying this technique to some special engine cases described in the following section and compare the numerical results with measu...

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Integral equation modeling of cylindrically periodic scatterers in the interior of a cylindrical waveguide

Cited by 19 publications

References 12 publications

Matrix decomposition algorithms for elliptic boundary value problems: a survey

Matrix decomposition algorithms for elliptic boundary value problems: a survey

Comparative study of miscellaneous methods applied to a benchmark, inlet scattering problem

Computation of radar cross section of jet engine inlets

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