查询词典 numerical computation

To improve the simulation accuracy and to make the increment of computation amount the smallest, the quantitative comparison was used to compare the effect of incident direction and difference accuracy on numerical dispersion with the changing of the ratio of horizontal and vertical gird. The results show that the rectangular grid is better than square mesh in suppressing dispersion and can avoid the low computational efficiency caused by high-order difference.

为提高模拟精度，同时又尽可能减少计算量，采用定量分析的方法，对比分析了横纵网格比变化时入射方向和差分精度等因素对数值频散的影响，分析结果表明，矩形网格较之正方形网格能更好地压制频散，同时可以避免高阶差分导致的低计算效率。

FLUENT is selected for the numerical simulation of hydrodynamic in fluidized bed because of the advantage of compute method and stabilization, astringency of computation of this software.

由于目前在硬件方面的限制，利用颗粒轨道模型对流化床进行模拟有很大的难度，而EULERIAN方法则可以以较少的计算花费得到两相各自的流体动力参数，同时也保证了计算的准确性、合理性，取得满意的结果。

In the process of numerical computation of electromagnetic field, primary ending voltage is taken as constraint condition, primary starting current is iterated, and stating current and starting torque at rated voltage is obtained.

在电磁场的数值计算过程中，以初级端电压为约束条件，对初级起动电流进行了迭代计算，得到了额定电压下的起动电流和起动转矩，最后把正弦电磁场计算结果与实测结果进行了对比，表明直线感应电动机起动性能的计算结果满足工程实际的需要。

The symplectic schemes have the ability to preserve the global symplectic structure of the phase space for a Hamiltonian system. They have substantial benefits in numerical computation for Hamiltonian system, especially in long-term simulations.

辛算法正是保持Hamilton系统内在性质的一种新型数值方法，该算法在长时间的数值计算中，具有常见数值方法无可比拟的计算优势。

In this paper, the maximum likelihood algorithm with process and measurement noise for nonlinear continuous-discrete system given by Jategaonkar and Plaetschke is improved in two aspects: 1 to avoid the disadvantages of sensitivities computation by common finite-difference method, in which the perturbation sizes should be selected optionally, an improved finite-difference method with best perturbations, is presented. 2 to improve the numerical stability of Jategaonkar's algorithm, maximum likelihood algorithm with fast triangular square-root decomposition filter is given.

摘要对Jategaonkar等人给出的同时计及过程及观测噪声的非线性连续-离散系统的极大似然算法从两个方面进行了改进：1给出了计算灵敏度的最佳摄动有限差分算法，避免了普通有限差分法计算灵敏度矩阵时需人为选择参数摄动量大小而带来的缺点；2给出了具有快速三角化平方根滤波的极大似然算法，提高了原算法的数值稳定性。

Then in order to improve the efficiency and accuracy of numerical computation, the author developed hybrid spline interpolation, automatically varia...

然后为了提高数值计算的精度和效率，作者又根据二次样条的特点，提出了杂交样条插值、可变节距样条求积和自适应的样条求导等新方法。

According to rate process theory, slip theory of plasticity and principle of virtual work, the micromechanical model of soil creep are set up, the numerical solution of the model is given, the differences and similarilities between frequency distribution function of microplane and clay platelet are discussed and schematic computation flow of the model for fitting the test data of homogeneously stressed anisotropically consoildated clay specimens in an undrained creep test at constant volume are given.

以速率过程理论作为土质学与土力学间的桥梁，根据塑性滑动理论和虚功原理，从微观结构的角度，建立了反映粘性土宏观应力应变关系的微观力学模型，给出了微观力学模型数值解的近似表达式，讨论了微滑面与粘粒和团粒定向频率分布的异同，设计了一个拟合各向异性土不排水蠕变的计算流程。

Second, it accomplishes numerical computation at different ignition temperature and combustion time of different coal quality in calciner.

本文的特色在于：一方面，针对水泥分解炉工况，首次在国内系统而全面的研究了煤的燃烧特性及相关规律；另一方面，实现了分解炉内不同煤质的着火温度和燃尽时间的数值计算，从而使水泥分解炉内，煤的燃烧理论研究朝着工程应用的方向迈进。

And what's more, a new definition of error is introduced for evaluation of the computation: The effect of Courant number, grid resolution and ratio of cell on numerical dispersion is analyzed too.

详细地研究了Courant数、网格分辨率CPW和网格长度比率等因素对于数值色散误差的影响，为基于Taylor差分格式的FDTD算法的研究提供了有用的参考。

According to by the time series estimate power spectral density\'s periodogram law principle,the research adopts five level of orbital power spectra which US Federal railway Administrative bureau FRA proposed;then,through the Fourier inverse transformation,the orbital not smooth time domain samples are obtained, which determine the track irregularity peak-to-peak value and the corresponding wave length; on the basis of the research,the influence of the wheel track dynamic contact force are considered.Based on the orbital roadbed coefficient\'s definition,computation model is established to solve the roadbed equispaced spring constant,and the roadbed uniform spring stiffness is obtained by using the numerical simulation method.Finally,based on the Matlab procedure platform,the computational procedure is established,and the load time interval caused by the moving train acts on the roadbed is obtained.

根据由时间序列估计功率谱密度的周期图法原理，采用美国联邦铁路管理局FRA提出的五级轨道功率谱，通过Fourier逆变换得到轨道不平顺的时域样本，确定了轨道不平顺的幅值及对应的波长，以此为基础考虑轮轨动态接触力的影响；基于轨道路基系数的定义建立了求解路基均布弹簧刚度的计算模型，采用数值模拟得到了路基均布弹簧刚度；最后，基于Matlab程序平台编制了计算程序，得到了运行列车作用到路基上的荷载时程。

There had been a moment during the breakfast meeting, though, after the backslapping and the small talk and when all of us were seated, with Vice President Cheney eating his eggs Benedict impassively and Karl Rove at the far end of the table discreetly checking his BlackBerry, that I witnessed a different side of the man.

那次早餐会期间，在表示过关心和寒暄以后，我们所有人坐了下来，我注意观察了一下，副总统切尼面无表情地吃着班尼迪克蛋（Eggs benedict，源自美国，以英式松饼、火腿、水煮蛋以及荷兰酱组合而成），卡尔。罗夫在餐桌的远端谨慎地经常查看他的黑莓手机，我目睹了他所不为人知的一面。

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