查询词典 finite difference approximation

It is shown that in Jameson's algorithm is not an orthogonal stream-lines coordinate system, but a local stream-lines coordinate system instead. Nevetheless, because of the finite-difference discretization in Jameson's scheme is not carried out along the direction of s and n, but along the Cartesian coordinates, the analysis on all terms of the full potential equation in Cartesian coordinates reveals that his scheme does take a back-ward difference along the streamwise exactly at all points in the supersonic flow region.

表明其所采用的坐标系不是真正的正交流线坐标系，而是局部流线坐标系；同时由于Jameson方法并不对s，n进行差分离散，而是在原笛卡尔坐标系下作差分离散，对笛卡尔坐标系下的全位势方程中的各项的分析表明，Jameson方法恰好能做到在超音速点沿真正的流线方向作后差分。

The difference between the differential and the finite-difference operator is however a primitive error source in the numerics.

然而，解析性微分算子和离散性差分算子的差异却是造成数值计算的原始误差源。

In this paper, a high order accuracy difference method is presented for solving unsteady convection diffusion equation by using Implicit Perturbation Finite Difference scheme.

本文利用摄动差分思想，对定常对流扩散方程中的空间微商系数进行摄动展开，展开幂级数系数通过消去摄动格式修正微分方程的截断误差项求出，由此获得方程的隐式摄动差分格式，将此方法应用于非定常对流扩散方程，并加以修正，得到该方程的修正隐式摄动差分格式。

Magnetic field method is used to analysis the distribution of multi-medium, complex boundary, large difference in dimension, non-linear and forced axial symmetry magnetic field in magnetic fluid seal, the data is derived by unequally spaced net finite difference, and the results of different structure are showed by magnetogram.

利用变步长有限差分法对磁场法描述的磁流体密封中磁介质多、边界复杂、尺寸差别大、非线性的强磁场进行求解，得到了多种形式密封结构磁力线和磁感应强度等值线的分析结果。

But the finite difference methods require that computational domain is regular, and usually people construct the difference scheme for one dimension and then extend it to two or three dimensions in a dimension by dimension fashion.

有限差分方法要求计算区域比较规则，而且人们往往是对一维方程构造差分格式，再用分裂方法将其推广到多维。

A combined super compact finite difference scheme is proposed.Numerical characteristics of CSCD is analysed and compared with other symmetric difference schemes.

提出一族组合型超紧致差分格式，对CSCD的数值特性作了分析，并同其他中心型差分格式进行比较。

FLAC~(3D) is for the analysis of the Lagrange explicit finite difference procedure for the timely steps to solve the dynamic relaxation, for when the difference method based on the show, less memory, faster solution. This paper discusses the usage of model FLAC create certainty and mixed model approach and to a dam seepage stability analysis as the research object, the establishment of a certainty piezometric level model, and further establish hybrid model, and the permeability coefficient for inversion analysis.

本文探讨了利用FLAC建立确定性模型和混合模型的方法，并以某土坝渗流稳定分析为研究对象，建立了测压管水位的确定性模型，进一步建立混合模型。

Finite Difference Time Domain method is adopted to evaluate the relationship between the off-axis angle of the beam and the temperature difference.

由时域有限差分方法得到光束偏转角度与温度差之间的关系。

The finite difference time-domain method is stable and easy to be used, but due to the fact that it approximates the space derivatives in Maxwells curlequations by central difference, FDTD usually requires more than 20 grids perwavelength to achieve acceptable accuracy. As a contrast, pseudospectraltime-domain method approximates the space derivatives by pseudospectralmethod, which guarantees the accuracy, theoretically requiting only 2 grids perwavelength.

传统的电磁场数值算法——时域有限差分法稳定而易于实现，但由于FDTD采用中心差分近似Maxwell旋度方程的微分，每个波长上需要取的网格数通常较多，而时域伪谱法采用伪谱法求微分，理论上每个波长只需要取两个网格便可以达到较高的精度。

Based on the error estimates of moving least-square approximation, the error estimates for the finite point method are obtained.

基于移动最小二乘法的误差公式，本文讨论了有限点法的误差估计。

We have something to do in the new stage.

在这段崭新的时期中，我们有一些要做的。

The difference between tourism decision-making under uncertainty and risky tourism decision-making is indistinctive.

其中不确定性旅游决策和风险旅游决策的界线比较模糊，两者的区分是相对的。