查询词典 backward difference

In the process of discretization of the auxiliary function, the traditional central difference formula is replaced by the backward difference formula, and numerical results show the method is of good stability.

在辅助函数的离散过程中用后向差分公式代替传统的中心差分公式，数值结果显示出良好的稳定性。

Douglas and Russell first presented the idea of characteristics in[13],in whichthe diffusion term is included in the derivative of characteristic direction of the solu-tion and the backward difference quotient along the time axis was replaced by it alongcharacteristic direction.

Douglas，Russell[13]最先提出了特征法的思想，其主要特点是将模型方程的对流项隐含在解沿特征方向的导数之中，以沿特征方向的向后差商逼近取代通常方法中沿时间方向的向后差商逼近。

There are three difference formats in this thesis. They are backward difference, Crank-Nicolson"s difference and Galerkin"s difference.

本文对时间域采用的离散格式有两点向后差分、Crank-Nicolson格式差分和Galerkin差分等。

Not only is the method applied in this paper better to solve the iteration between unsteady convection and conduction and the boundary condition problem, but also is a developmental application on forward and backward difference of windward scheme under unsteady condition.

不仅较好地解决了对流换热和导热的迭代求解和边界条件的处理问题，还将迎风格式的向前和向后差分发展性地应用于非稳态求解过程。

Founds three-dimensional analytic model and analyses heat transfer with phase change with the help of numerical simulation software using Euler backward difference.

通过实验分析了冰水两相流在垂直和水平管道流动时的压降特性；建立了冰融解的三维分析模型，采用欧拉向后差分法，利用ANSYS数值模拟软件对冰水相变传热进行了数值模拟分析，得出冰粒大小与融解时间两者的关系曲线。

Central difference method and backward difference method were used for transient thermal analyzing,and the result suggested that two methods have same accurate for this problem.

太阳辐射热流、地球红外辐射热流及地球反照热流是航天器产生不均匀时变温度场主要热量来源。

By analyzing the reason of the numerical oscillation phenomenon and computing the temperature field in plate rolling process,it is found that numerical oscillation can be restrained effectively when the heat capacity matrix is lumped by using backward difference scheme.

近年来，许多研究人员采用有限元法分析热轧和淬火等过程中的瞬态温度场。

An improved derivative estimation algorithm with a low-pass filter that can suppress the influence of high-frequency noise is suggested to remove potential drawbacks of the backward difference that was applied in neural network inversion dynamic compensation method, such as large estimation error in the presence of noise and price increase of hardware realization when high estimation accuracy is required.

针对神经网络逆动态补偿策略中基于向后差分的微分估计算法在噪声环境下存在较大的微分估计误差，且提高估计精度会增加硬件成本等缺陷，提出了改进的微分估计算法，并以加速度传感器为例，设计了动态补偿实验装置，给出了基于改进的微分估计算法的动态补偿算法的实现步骤。

The control volume integration was applied to deduce the discrete expressions of the convection-diffusion equations. The staggered grid and SIMPLE algorithm were introduced to deal with coupling between pressure and velocity, and then the numerical computation expressions of such variables as fluid flow velocity and pressure were deduced. Using the backward difference method and incremental theory to discretize the governing equations for fields of chemical reaction, material structure and chemorheology, the numerical computation expressions of variables such as the monomer conversion, average molecular weight and fluid viscosity were constructed.

应用控制容积积分法导出了对流—扩散方程的离散表达式，引入交错网格技术与SIMPLE算法，实现了耦合的压力场与速度场的分离式求解，推导得到了流体的流动速度、压力等物理量的数值计算式；采用向后差分方法和增量方法，实现了化学反应场、材料结构场、化学流变场控制方程的离散，获得了反应转化率、聚合物平均相对分子质量、流体黏度等物理量的数值计算式。

Because the diffusive term is discretized with divided forward difference or divided backward difference according to the sign of convection velocity, these methods keep first order accuracy for diffusive term.

3.2考虑规则网格上的一维和二维定常型对流占优扩散问题，离散方法采用了有限体积方法及普通的有限差分方法，基本离散思想是将对流项提高到二阶精度，扩散项则根据对流速度的方向决定采用向前或向后差商离散。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。