理想边界

The stream function equations are derived, based on the fluid equations of motion on a revolving S 1 stream surface in centrifugal pump impeller, for indirect boundary element method. The equations are suitable ideal and incompressible fluid flow with rotation or non rotation in absolute coordinate system.

根据离心泵叶轮S1流面的流体运动方程，推导了间接边界元法所需的流函数方程，它适用于不可压理想流体的绝对流动有旋或无旋流动。

Based on varying process of generator terminal parameters after excitation fault, shortages of excitation protective principle of static stability boundary and asynchronous impedance boundary are analyzed. It proposed that excitation fault research relates to large-disturbance stability. Because dynamic power-angle character of generator after excitation fault is non-sinusoidal, there are differences between dynamic power-angle character and static state power-angle character. So it isn't ideal to protective operation result based on small-disturbance stability and static stability boundary criterion. At the same time, it proposed that asynchronous boundary impedance criterion is a constant reactive power circle moving adown j Xd′. It can ensure complete loss-of-excitation generator measuring impedance enter into the circle, but can't ensure the other condition measuring impedance including impossible losing synchronism enter. So loss-of-excitation protection would be maloperation when system voltage drops short and recovers or generator rejects load.③Based on stability principle, it puts forward setting conditions and calculation method of generator loss-of-excitation protection by direct measuring power-angle.

以励磁故障后发电机端的相关参数的变化为基础，通过对以静稳定边界和异步阻抗边界作判据的两类三种现行励磁保护在原理上存在的缺陷分析，发现：励磁故障是一个大干扰稳定性问题，励磁故障后的发电机的动态功角特性与静态功角特性有很大的差异，已远非正弦曲线，因此基于小干扰稳定性原理、以静稳定边界作判据的保护必然动作不理想；异步边界阻抗判据是一个下移j Xd′的等无功阻抗圆，它可以保证完全失磁后的发电机测量阻抗能进入该阻抗圆，但不能保证完全失磁之外的其它状态不会进入该阻抗圆，因此在系统电压短时下降或发电机突然甩负荷等情况下可能启动该保护使之误动。

The Allium cowanii is ideal for containers, mass plantings, borders, and cut flowers.

该葱cowanii是理想的容器，大规模的种植，边界，切花。

Good natured, placid in basic disposition and fond of children, very devoted, obedient, biddable and eager to work.

理想的洛威纳犬是一个中等大小，精力充沛而且非常有力的狗，黑色配有边界清晰的铁锈色斑纹。

The results show that, when the computational error and its accumulation are eliminated effectively, the laminar flow in OFR with perfect-symmetric boundaries behaves in a pattern of central symmetry and circumferential uniformity while the turbulent flow field presents a centrally symmetric and circumferentially non-uniform structure with 8 transverse vortices arrayed circumferentially in a way of central symmetry, similar to Taylor vortices in Couette flow.

模拟结果表明在有效消除计算随机误差以及误差积累的情况下，几何边界理想对称OFR内的三维层流流场呈现出良好的中心对称性和周向均匀性，而湍流流场中心对称的同时呈现出周向非均匀结构－在圆周上生成8个中心对称排列的横向漩涡，其形态与Couette流中的泰勒涡类似。

Some curvilinear grid generation examples show that the proposed adjusting factors ideal grids can be formed for simple connected regions and connected regions with complex boundary. The curvilinear grids near boundaries are orthogonal ...

实例检验表明，该调节因子能够对复杂边界的单连通域或多连通域的水域生成理想的曲线网格，即边界处网格正交，内部网格分布能够适应物理量场的变化情形。

But in 1744,d\'Alembert found that if we consider the fluid as no viscosity,the results of the theoretical analysis are different from the experiment.

实验表明粘性流体的运动，在区域内部趋向于理想流体的流动，在边界附近表现为边界层的流动。

Research results show that the latter is more suitable to describe the artificial boundary accuracy of near-field wave motion decoupling numerical simulation, and the former can be used to estimate the upper limit of artificial boundary error.

研究结果表明：理想暂态情形下的反射系数，更适合描述近场波动解耦数值模拟中的人工边界精度；而理想稳态情形下的反射系数可用于估计人工边界误差的上限。

Numerical results for perfectly conduction and homogeneous penetrable circular cylinder are presented and compared with the solutions by using second-order differential operator B2 type absorbing boundary condition.

本文使用这种边界条件对理想导电及均匀电磁可穿透材料圆柱散射体的表面场进行了数值计算，并与使用二阶微分算子B_2型的吸收边界条件的结果作了比较。

FEMOL is systematically applied to various moving boundary problems, including: membranes contact with rigid foundation, shape optimization of cross-sections of elastic torsional bar, seepage through a dam with a free surface, Mindlin-Reissner plates contact with rigid foundation, free Mindlin-Reissner plates on tensionless

三、将有限元线法分析推广应用到了一系列的动边界问题中，包括：薄膜接触问题，弹性扭转杆的截面优化问题，自由液面的稳定渗流问题，中厚板理论与刚性地基的接触问题，无拉力Winkler地基上自由中厚板问题，理想弹塑性扭转问题，理想弹塑性Ⅲ型裂纹问题。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了