A Finite Element Conjugate Gradient FFT Method for Scattering PDF Download
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Author: National Aeronautics and Space Adm Nasa
Publisher:
ISBN: 9781729124468
Category :
Languages : en
Pages : 26
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Book Description
An extension of a two dimensional formulation is presented for a three dimensional body of revolution. With the introduction of a Fourier expansion of the vector electric and magnetic fields, a coupled two dimensional system is generated and solved via the finite element method. An exact boundary condition is employed to terminate the mesh and the fast fourier transformation (FFT) is used to evaluate the boundary integrals for low O(n) memory demand when an iterative solution algorithm is used. By virtue of the finite element method, the algorithm is applicable to structures of arbitrary material composition. Several improvements to the two dimensional algorithm are also described. These include: (1) modifications for terminating the mesh at circular boundaries without distorting the convolutionality of the boundary integrals; (2) the development of nonproprietary mesh generation routines for two dimensional applications; (3) the development of preprocessors for interfacing SDRC IDEAS with the main algorithm; and (4) the development of post-processing algorithms based on the public domain package GRAFIC to generate two and three dimensional gray level and color field maps. Collins, Jeffery D. and Zapp, John and Hsa, Chang-Yu and Volakis, John L. Unspecified Center ...
Author: National Aeronautics and Space Adm Nasa
Publisher:
ISBN: 9781729124468
Category :
Languages : en
Pages : 26
Get Book Here
Book Description
An extension of a two dimensional formulation is presented for a three dimensional body of revolution. With the introduction of a Fourier expansion of the vector electric and magnetic fields, a coupled two dimensional system is generated and solved via the finite element method. An exact boundary condition is employed to terminate the mesh and the fast fourier transformation (FFT) is used to evaluate the boundary integrals for low O(n) memory demand when an iterative solution algorithm is used. By virtue of the finite element method, the algorithm is applicable to structures of arbitrary material composition. Several improvements to the two dimensional algorithm are also described. These include: (1) modifications for terminating the mesh at circular boundaries without distorting the convolutionality of the boundary integrals; (2) the development of nonproprietary mesh generation routines for two dimensional applications; (3) the development of preprocessors for interfacing SDRC IDEAS with the main algorithm; and (4) the development of post-processing algorithms based on the public domain package GRAFIC to generate two and three dimensional gray level and color field maps. Collins, Jeffery D. and Zapp, John and Hsa, Chang-Yu and Volakis, John L. Unspecified Center ...
Author: Jeffrey D. Collins
Publisher:
ISBN:
Category : Conjugate gradient methods
Languages : en
Pages : 146
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Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 73
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Book Description
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722891985
Category :
Languages : en
Pages : 154
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Book Description
A new technique is presented for computing the scattering by 2-D structures of arbitrary composition. The proposed solution approach combines the usual finite element method with the boundary integral equation to formulate a discrete system. This is subsequently solved via the conjugate gradient (CG) algorithm. A particular characteristic of the method is the use of rectangular boundaries to enclose the scatterer. Several of the resulting boundary integrals are therefore convolutions and may be evaluated via the fast Fourier transform (FFT) in the implementation of the CG algorithm. The solution approach offers the principle advantage of having O(N) memory demand and employs a 1-D FFT versus a 2-D FFT as required with a traditional implementation of the CGFFT algorithm. The speed of the proposed solution method is compared with that of the traditional CGFFT algorithm, and results for rectangular bodies are given and shown to be in excellent agreement with the moment method. Collins, Jeffery D. and Volakis, John L. Unspecified Center BOUNDARY INTEGRAL METHOD; FAST FOURIER TRANSFORMATIONS; FINITE ELEMENT METHOD; WAVE SCATTERING; ALGORITHMS; COMPUTATIONAL GRIDS; COMPUTER SYSTEMS PERFORMANCE; MEMORY (COMPUTERS); METHOD OF MOMENTS; WAVE EQUATIONS...
Author: KASRA BARKESHLI
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 592
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Book Description
finite number of steps. Moreover, since the CGFFT algorithm is highly vectorizable, it can be efficiently implemented on supercomputers and multiprocessor machines.
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 562
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Book Description
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722128135
Category :
Languages : en
Pages : 56
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Book Description
A method for the computation of electromagnetic scattering from arbitrary two-dimensional bodies is presented. The method combines the finite element and boundary element methods leading to a system for solution via the conjugate gradient Fast Fourier Transform (FFT) algorithm. Two forms of boundaries aimed at reducing the storage requirement of the boundary integral are investigated. It is shown that the boundary integral becomes convolutional when a circular enclosure is chosen, resulting in reduced storage requirement when the system is solved via the conjugate gradient FFT method. The same holds for the ogival enclosure, except that some of the boundary integrals are not convolutional and must be carefully treated to maintain O(N) memory requirement. Results for several circular and ogival structures are presented and shown to be in excellent agreement with those obtained by traditional methods. Collins, Jeffery D. and Jin, Jian-Ming and Volakis, John L. Unspecified Center...
Author: kasro barkeshli
Publisher:
ISBN:
Category :
Languages : en
Pages : 104
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Book Description
Author: Kasra Barkeshli
Publisher:
ISBN:
Category : Conjugate gradient methods
Languages : en
Pages : 93
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Book Description
Author: John L. Volakis
Publisher: John Wiley & Sons
ISBN: 9780780334250
Category : Science
Languages : en
Pages : 364
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Book Description
Employed in a large number of commercial electromagnetic simulation packages, the finite element method is one of the most popular and well-established numerical techniques in engineering. This book covers the theory, development, implementation, and application of the finite element method and its hybrid versions to electromagnetics. FINITE ELEMENT METHOD FOR ELECTROMAGNETICS begins with a step-by-step textbook presentation of the finite method and its variations then goes on to provide up-to-date coverage of three dimensional formulations and modern applications to open and closed domain problems. Worked out examples are included to aid the reader with the fine features of the method and the implementation of its hybridization with other techniques for a robust simulation of large scale radiation and scattering. The crucial treatment of local boundary conditions is carefully worked out in several stages in the book. Sponsored by: IEEE Antennas and Propagation Society.
