查询词典 finite difference approximation

First of all,we construct a semidiscrete finite difference scheme to Burgers equation with initial condition and Dirichret boundary conditions.

首先，对Burgers方程的初边值问题建立了一个半离散的有限差分格式。

Continuity equation and motion equation which can be applied to cone-shaped pipes are obtained and finite difference method for them is brought forward.

根据非稳定流的一维流动理论，对圆锥形管道中的瞬变流动进行了分析，推导出了适用于圆锥形管道的连续性微分方程和运动微分方程，给出了这两个方程的有限差分解法，同时对计算结果进行了相对误差的对比分析。

That is the finite difference equations are not consistent with the differential equations of non- Newtonian fluids in porous media.

如何把流体的非牛顿行为用差分方法恰当地表示出来，是油藏数值模拟需要研究的课题之一。

This paper studies semi-discrete finite difference methods of constant coefficient heat equations .

本文主要研究了常系数热传导方程的半离散有限差分方法。

Firstly, the approach formulates a cost functional to turn the inverse problem into a constrained minimization problem according to least squares criterion, then the resulting constrained minimization problem is transformed into an unconstrained minimization problem by using a penalty function technique, and then the closed Fr chet derivatives of the Lagrange function with respect to the properties are derived based on the calculus of variations, finally, one can solve the resulting problem by using any gradient-based algorithm and the finite-difference time-domain method.

该方法首先以最小二乘准则构造目标函数，将逆问题表示为约束最小化问题；接着应用罚函数法转化为无约束最小化问题；然后基于变分计算导出闭式的拉格朗日函数关于特征参数的Fr chet导数；最后借助梯度算法和时域有限差分法迭代反演德拜模型参数。

The extracted P-wave is reverse-time extrapolated and imaged with a P-velocity model using a finite difference solution of the scalar wave equation, the extracted S-wave is reverse-time extrapolated and imaged similarly, but with an S-velocity model, and converted S-wave data requires a polarity correction prior to migration to ensure constructive interference between data from adjacent source.

在模型中，每个网格点的纵、横波成像时间，为震源到该网格点的纵波初至时间。利用纵波速度模型和声波传播方程的有限差分解，对反射纵波进行逆时延拓和成像，利用横波速度模型和声波传播方程的有限差分解，对转换横波进行逆时延拓和成像，并在偏移前进行极性校正。

In the thesis, the fundamental formula of FFD method derives from the square root that is approximated by a continued fraction expansion in the one-way wave equation. Optimizations of the parameters of the finite-difference operator improve the validity of the method.

本论文用连分式近似单程波波动方程中的平方根导出FFD算法的基本公式，并对FFD算法中的有限差分算子进行了系数优化，进一步提高了计算的有效性。

The PSE in the curve coordinate systems are solved by the numerical techniques developed efficiently in this paper. A normal transform is introduced, and there are enough much grids in the region between the critical layer and the wall, where the variation of the disturbance is the quickest. The finite-difference of governing equations with fourth-order accuracy in the normal direction is utilized in full regions including points close the wall, and is very important for accurately discreting equations.

对于曲线坐标系下的抛物化稳定性方程，文中发展了求解的高效数值方法：引进法向变换，使得在临界层与壁面之间的扰动量变化最快的区域有更多的法向网格点；导出包含边界邻域在内的完全四阶精度的法向有限差分格式，这对方程精确离散至关重要；采用全局法和局部法相结合的方法及其新的迭代公式，大大加速收敛并得到更精确的特征值。

The finite difference method is adopted to calculate the temperature field on cross-section of the column, the critical temperature and the critical time, the thickness of fire resisting covering of CFST columns, All of the results were verified by experiments.

简要地介绍了钢管混凝土的耐火性能，分析了影响耐火度的因素以及用有限差分法计算火灾时的构件截面的温度场、构件的临界温度和临界时间、防火涂层厚度的结果。

There are fourteen chapters, including introduction, plane stress and plane strain, two-dimensional problems in rectangular coordinates, two-dimensional problems in polar coordinates, photoelastic and moire experimental methods, two-dimensional problems in curvilinear coordinates, analysis of stress and strain in three dimensions, general theorems, torsion, bending of bars, axisymmetric stress and deformation in a solid of revolution, thermal stress, the propagation of waves in elastic solid media, at last there is an appendix on the application of finite-difference equations in elasticity.

全书共十四章，包括绪论、平面应力和平面应变、直角坐标中的二维问题、极坐标中的二维问题、光弹性与云纹实验方法、曲线坐标中的二维问题、三维应力和应变问题、一般定理、简单的三维弹性问题、扭转、杆的弯曲、回转体中的轴对称应力和变形、热应力、弹性固体介质中波的传播，最后有一附录，讲述差分方程在弹性理论中的应用。

He has to relate with three women in the movie, and yet remain implicitly faithful to the unseen Lucinda.

让克劳德布里亚里成功地饰演试验了一个难度很大的角色：和三个女人打交道，但还要底下对观众未曾谋面的卢馨达保持忠诚。

The experiment was conducted to study effects of inulin on the growth performance, indices of immune organs and serum immunoglobulin of laying chicklings as well as the performance of inulin which replaced the antibiotics in diets by adding 0.2%, 0.4% and 0.8% of inulin, respectively.

试验旨在通过在蛋用雏鸡日粮中添加0.2%、0.4%和0.8%的菊粉，研究菊粉对蛋雏鸡生长性能、免疫器官指数和血清免疫球蛋白的影响，以及菊粉替代抗生素对蛋雏鸡的应用效果。