A new method to reduce the numerical dispersion of the three-dimensional Alternating Di-rection Implicit Finite-Difference Time-Domain (3-D ADI-FDTD) method is proposed. Firstly,the numerical formulations of the 3-D A...A new method to reduce the numerical dispersion of the three-dimensional Alternating Di-rection Implicit Finite-Difference Time-Domain (3-D ADI-FDTD) method is proposed. Firstly,the numerical formulations of the 3-D ADI-FDTD method are modified with the artificial anisotropy,and the new numerical dispersion relation is derived. Secondly,the relative permittivity tensor of the artificial anisotropy can be obtained by the Adaptive Genetic Algorithm (AGA). In order to demon-strate the accuracy and efficiency of this new method,a monopole antenna is simulated as an exam-ple. And the numerical results and the computational requirements of the proposed method are com-pared with those of the conventional ADI-FDTD method and the measured data. In addition the re-duction of the numerical dispersion is investigated as the objective function of the AGA. It is found that this new method is accurate and efficient by choosing proper objective function.展开更多
基于贴体平面二维正交曲线网格,建立了河道二维非恒定流的数学模型,采用交替方向隐格式法(Alternating Direction Implicit Method简称ADI法)对二维浅水方程进行了差分离散求解。在离散过程中,对对流项采用一阶迎风格式,以克服由于对流...基于贴体平面二维正交曲线网格,建立了河道二维非恒定流的数学模型,采用交替方向隐格式法(Alternating Direction Implicit Method简称ADI法)对二维浅水方程进行了差分离散求解。在离散过程中,对对流项采用一阶迎风格式,以克服由于对流项采用中心差分而引起的不稳定。以长江南通河段为例,对模型进行了验证计算。计算结果表明,模型能较好地模拟复杂条件下天然河道的水流基本规律。展开更多
基金the National Natural Science Foundation of China (No. 60271012)Research Foundation of ZTE Corporation.
文摘A new method to reduce the numerical dispersion of the three-dimensional Alternating Di-rection Implicit Finite-Difference Time-Domain (3-D ADI-FDTD) method is proposed. Firstly,the numerical formulations of the 3-D ADI-FDTD method are modified with the artificial anisotropy,and the new numerical dispersion relation is derived. Secondly,the relative permittivity tensor of the artificial anisotropy can be obtained by the Adaptive Genetic Algorithm (AGA). In order to demon-strate the accuracy and efficiency of this new method,a monopole antenna is simulated as an exam-ple. And the numerical results and the computational requirements of the proposed method are com-pared with those of the conventional ADI-FDTD method and the measured data. In addition the re-duction of the numerical dispersion is investigated as the objective function of the AGA. It is found that this new method is accurate and efficient by choosing proper objective function.
文摘基于贴体平面二维正交曲线网格,建立了河道二维非恒定流的数学模型,采用交替方向隐格式法(Alternating Direction Implicit Method简称ADI法)对二维浅水方程进行了差分离散求解。在离散过程中,对对流项采用一阶迎风格式,以克服由于对流项采用中心差分而引起的不稳定。以长江南通河段为例,对模型进行了验证计算。计算结果表明,模型能较好地模拟复杂条件下天然河道的水流基本规律。
