数值算法

The non-structure grid is used for complex irregular boundary processing. An efficient algorithm PISO is used for the model and it can correct the bias of the mesh, so it can reduce iterative times. The flow pattern, energy dissipation ratio and velocity field are obtained.

根据不同的运行工况，利用计算流体力学软件FLUENT对无压隧洞洞内消能工的水流流态进行了二维简化数学模型的数值模拟，在求解过程中采用混合结构网格来处理复杂的边界形状；采用了效率较高PISO算法进行计算，在计算过程中进行了相邻校正和偏斜校正，减少了达到收敛所需的迭代次数。

VOF method was used to track the shape and location of free face, and PISO method was used to couple the velocity field and pressure field. By the 2-D and 3-D numerical simulations of the flow in sprinkler component under different states, the preliminary flow law of the sprinkler was revealed for the first time.

6采用三维非定常N-S方程作为控制方程，利用标准κ-ε紊流模型封闭雷诺时均方程，并利用VOF方法求解追踪自由表面的形状和位置，采用PISO算法耦合速度压力场，首次对喷头射流元件内部流动的不同运行状态进行了二维、三维数值模拟，初步揭示了内部流动的一般规律。

Therefore,the pseudospectral time-domain method was used to solve the equations of cold plasma.

这与用高阶2TD方法数值模拟结果一致，表明时域伪谱算法模拟电磁波在电离层中长距离传播的有效性。

In the last chapter of this paper, several remarks of this study were discussed. Considering saving the computer memory and increasing the calculation speed, the Pseudospectral time-domain numerical method is more effective than the FDTD method.

从节约计算机内存和提高计算速度方面考虑，电磁场数值计算建议采用时域伪谱算法来代替时域有限差分法，并进行了相应的比较和分析。

We also measure the distance and section of some muscles for example, psoas major muscle, quadratus lumborum, erector spinae olbique, internal abdominal oblique, rectus abdominis, transversus abdominis.

运用横截面积肌力计算法，测量尸体腰椎周围肌肉：腰大肌、腰方肌、竖脊肌、腹内外斜肌、腹横肌的解剖横断面积，及其与腰段脊柱纵轴的中心距数值，求得力矩值。

In order to select optimal grid and good computation efficiency to recover the entire signal, aiming at the Ricker wavelet commonly used in forward modeling, we analyzed the alias and signal restoration problem in finite-difference method based on spatial sampling theorem and seismic wave traveling regulation in media with different velocity, to derive quantitative relationship among the modeling grid size, minimum velocity of model layer, and recovered main frequency of wavelet.

为了选择最佳的网格尺寸以及以最小的计算量完整地恢复出信号，针对地震波场正演模拟中经常使用的Ricker子波，根据空间采样定理和地震波在不同速度介质中的传播规律，分析了有限差分算法中的假频和信号恢复问题，推导出模拟网格尺寸、模型地层的最小速度和能够恢复的子波主频之间的近似定量关系，并用数值算例验证了这一关系。

Level set method introduced by Osher and Sethian is a numerical method, which translates the problem of evolution of 2-D (3-D) close curve into the evolution of level set function in the space with higher dimension. Level set is an accurate and steady algorithm; it can treat with the change of topology naturally.

水平集方法是由Osher和Sethian提出的一种数值计算方法，它将二维的闭合曲线的演化问题转化为高维空间中水平集函数曲面演化的隐含方式来求解，具有拓扑结构可自然变化、计算精度高、算法稳定的特点。

In this paper, a procedure of nonlinear analysis of the cable-stayed bridge was developed based on the nonlinear theory of structures using the finite element method, in which the vehicle-bridge interaction element based on the concept of dynamic condensation is used. The influence of vehicles on the response of the cable-stayed bridge is studied by employing the spung mass model and the bridge model with and without considering cable vibration modes.

本文拟应用非线性力学分析程序与有限元素数值计算法，建立斜张桥的非线性分析程序，应用VBI的车桥互制元素配合动态浓缩的观念，以悬浮移动质量模拟车体对斜张桥的影响，并对考虑与不考虑缆索振动模态两种分析模型，做一对应分析比较。

Considering algorithm performance, numerical characteristic and parallelism, QRD-SMI is more suitable for real time implementation of STAP.

综合比较算法性能、数值特性以及可并行实现性，QRD-SMI更适合在STAP的工程实现时采用。

For various kinds of surfaces used in S_SOLID, a new surface/surface intersection algorithm is presented which adopts analytical, numerical, geometrical, subdivisional, and implicitizational methods.

针对S_SOLID系统中采用的各种几何表面，设计了一种解析、数值、几何、分割和隐函化相结合的曲线曲面求交算法。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。