排序方式: 共有66条查询结果,搜索用时 15 毫秒
51.
Omar Ramadan 《International Journal of Infrared and Millimeter Waves》2005,26(8):1151-1161
In this paper, unsplit-field Perfectly Matched Layer (PML) formulations are presented for truncating nonlinear dispersive Finite Difference Time Domain (FDTD) grids. The proposed scheme is based on incorporating the nonlinear Z-transform FDTD algorithm into the Auxiliary Differential Equation PML (ADE-PML) formulations. Numerical example carried out in one dimensional domain which includes Lorentz dispersion as well as Kerr and Raman nonlinearities is included to show the validity of the formulations. 相似文献
52.
Dan Zhang Hongting Jia Kiyotoshi Yasumoto 《International Journal of Infrared and Millimeter Waves》2007,28(11):1003-1010
We analyzed the frequency and quality factor of microcavities on a two-dimensional photonic crystal, using a Fourier series
expansion method combined with perfectly matched layers (PMLs). Numerical examples are demonstrated and discussed to show
that the resonant frequency and the quality factor Q values can be calculated by the present method using PMLs. 相似文献
53.
The Casimir interaction energy due to the vacuum fluctuations of a massive vector field between two perfectly conducting concentric spherical bodies is computed. The TE contribution to the Casimir interaction energy is a direct generalization of the massless case but the TM contribution is much more complicated. Each TM mode is a linear combination of a transverse mode which is the generalization of a TM mode in the massless case and a longitudinal mode that does not appear in the massless case. In contrast to the case of two parallel perfectly conducting plates, there are no TM discrete modes that vanish identically in the perfectly conducting spherical bodies. Numerical simulations show that the Casimir interaction force between the two bodies is always attractive. 相似文献
54.
Numerical interaction of boundary waves with perfectly matched layers in two space dimensional elastic waveguides 总被引:1,自引:0,他引:1
Perfectly matched layers (PMLs) are now a standard approach to simulate the absorption of waves in open domains. Wave propagation in elastic waveguides has the possibility to support back-propagating modes (propagating modes with oppositely directed group and phase velocities) with long wavelengths. Back-propagating modes can lead to temporally growing solutions in the PML. In this paper, we demonstrate that back-propagating modes in a two space dimensional isotropic elastic waveguide are not harmful to a discrete and finite width PML. Analysis and numerical experiments confirm the accuracy and stability of the PML. 相似文献
55.
An efficient method to compute the scattering of a guided wave by a localized defect, in an elastic waveguide of infinite extent and bounded cross section, is considered. It relies on the use of perfectly matched layers (PML) to reduce the problem to a bounded portion of the guide, allowing for a classical finite element discretization. The difficulty here comes from the existence of backward propagating modes, which are not correctly handled by the PML. We propose a simple strategy, based on finite-dimensional linear algebra arguments and using the knowledge of the modes, to recover a correct approximation to the solution with a low additional cost compared to the standard PML approach. Numerical experiments are presented in the two-dimensional case involving Rayleigh–Lamb modes. 相似文献
56.
Tomek Bartoszynski Saharon Shelah 《Proceedings of the American Mathematical Society》2002,130(12):3701-3711
We will show that there is no example of a set distinguishing between universally null and perfectly meager sets.
57.
Jianxiong Li Jufeng Dai Peng Wan 《International Journal of Infrared and Millimeter Waves》2007,28(11):1011-1024
Based on the Z-transform method, a simple, efficient and unsplit-field implementation of the Stretched Coordinate Perfectly Matched Layer
(SC-PML) is proposed for truncating the nonlinear dispersive Finite Difference Time Domain (FDTD) lattices. In addition, the
nonlinear FDTD formulations using the Z-transform method are reformulated with the advantage of a simple derivative process. The proposed algorithm is validated
through two numerical examples carried out in one dimensional and two dimensional domains which include Lorentz dispersion
as well as Kerr and Raman nonlinearities. 相似文献
58.
59.
Seungil Kim 《Journal of Mathematical Analysis and Applications》2010,361(2):420-430
In this paper, we study the spectrum of the operator which results when the Perfectly Matched Layer (PML) is applied in Cartesian geometry to the Laplacian on an unbounded domain. This is often thought of as a complex change of variables or “complex stretching.” The reason that such an operator is of interest is that it can be used to provide a very effective domain truncation approach for approximating acoustic scattering problems posed on unbounded domains. Stretching associated with polar or spherical geometry lead to constant coefficient operators outside of a bounded transition layer and so even though they are on unbounded domains, they (and their numerical approximations) can be analyzed by more standard compact perturbation arguments. In contrast, operators associated with Cartesian stretching are non-constant in unbounded regions and hence cannot be analyzed via a compact perturbation approach. Alternatively, to show that the scattering problem PML operator associated with Cartesian geometry is stable for real nonzero wave numbers, we show that the essential spectrum of the higher order part only intersects the real axis at the origin. This enables us to conclude stability of the PML scattering problem from a uniqueness result given in a subsequent publication. 相似文献
60.
采用本征模展开法(EME)结合完全匹配层(PML)边界条件,研究了由TiO2和SiO2复合膜结构组成的平面光子晶体Bragg微腔的模式特性,分析了介质厚度无序对微腔模式的调制以及入射角对局域长度的影响.结果表明,若光束正入射,带边局域长度要大于禁带局域长度,随着无序度的增加光子通带的透过率逐渐降低,而禁带的透过率逐渐上升.当无序度较小时,局域长度随随机度的变化在带边和禁带内表现出相反的规律.当无序度较大时,局域长度不仅和随机度、带隙有关,还受到材料的影响;若光束斜入射,TE模的局域长度要远小于TM模对应的值,且其最小值向短波方向移动。此外,入射角和膜层数的变化都会导致局域长度的起伏. 相似文献