查询词典 difference boundary value problem

Boundary features are the boundary lines of a group of points distributed on a fitting feature.

边界特徵之萃取理论是利用拟合特徵所给予之资讯，找出属於边界之点云资料，再由这些边界点云资料计算出边界特徵。

The total transmission ratio, the relationship between basic transmission ratio and closed transmission ratio and their influences on efficiency were studied on the H typed closed epicyclic train, and the expression of boundary region of basic transmission ratio under conditions of satisfying the allowable efficiency was gained and the boundary curve was drawn.

研究了H封闭式周转轮系总传动比、基础传动比与封闭传动比之间的关系及其对效率的影响，得到了在满足许用效率的条件下基础传动比边界区域表达式，绘出了边界曲线。

The improved e-N method can also yield results well agree with those obtained by DNS.4 The transition prediction for boundary layers on cones with different key parameters such as angle of attack, cone half angle and the Mach number of the coming flow, have been made, to show the reliability of the modified e-N method.5 For the calculation of base flow, boundary layer equations can be used in the case of small angle of attack.

但是它要依赖于对初始扰动的正确预估，这显然又取决于更多飞行数据的积累和分析。e-N方法的转捩预测结果与直接数值模拟得到的结果也吻合较好。4通过对不同来流攻角、不同半锥角和不同马赫数的三维圆锥边界层的转捩位置进行预测，证实了改进的e-N方法对于三维边界层转捩预测是可靠的。5对于基本流的计算，边界层方程可以用于小攻角的情况，其计算量远远小于直接数值模拟，但背风面的剖面不可靠。

According to the studied results at present, the studied objects are mainly thin plate and beam about sound radiation mode, a method computed sound radiation mode of complex structure is presented in this dissertation, according to the results of the previous two chapter, a theoretical method to solve acoustical radiation mode and acoustical radiation efficiency of complex structure by boundary element method and acoustical radiation theory is posed, the acoustical radiation power is expressed as a Hermitian quadratic form, while the radiation modes is determined by general eigenvalue decomposing, and then the radiation efficiency is computed via the orthodoxy of radiation modes with regard to impedance matrix and average velocity matrix; lastly, the validity of the method is proved by pulsating sphere and radiating cube with analytical results. According to results of the form three chapter, the structure sound radiation sensitivity is studied in detail, the sound radiation power of structure can be expressed as positive Hermitian quadratic form, the sound radiation sensitivity can be expressed as two parts by partial differential with respect to design variable, which are sensitivity of boundary velocity and impedance matrix, combined with the theory of FEM and BEM, the structure sound radiation can be translated to the analysis of structure dynamic sensitivity and impedance matrix sensitivity. The theory posted in this dissertation is tested by the FEM software ANSYS and the software AAS programmed by author.

在前几章的基础上，通过结构声辐射的模态理论对结构的声辐射的机理进行了深入地探讨，针对目前声辐射模态的研究对象主要是简单的板和梁类结构，提出了一种计算复杂结构声辐射模态的方法，利用前两章研究所得的结论，将边界元方法与广义特征值的理论结合起来研究了复杂结构的声辐射模态与声辐射效率，先将结构的声辐射功率表示为一个正定的厄米特二(来源：ABb7C论文0909网www.abclunwen.com)次型，运用广义特征值分解求解了复杂结构的声辐射模态，然后利用声辐射模态关于阻抗矩阵与均方速度耦合矩阵的正交性，求解了复杂结构的声辐射效率，最后用具有解析解的脉动球与辐射立方体验证了该方法的有效性。

However the lower order traditional absorbing boundary conditions are only effective for the incident waves with smaller incident angles. A fourth-order absorbing boundary condition equation based on Higden's ABC is deduced in this thesis, and a new algorithm is presented to automatically select the Higden's parameters.

本文基于Higdon提出的吸收边界条件方法，推导出四阶吸收边界条件方程，并提出了一种新的吸收边界条件角度参数的自动选择方法，使该吸收边界条件能够吸收全角度(0～90度)入射波。

By using them, we can discuss the theory of holomorphic functions on domains: the characterization of zeros sets of holomorphic functions on the boundary, the characterization of A infinity interpolation sets on the boundary, etc.

对于复椭球和广义复椭球，我们给出了其全纯支撑函数的估计，构造了边界上的拟距离，并用这些结果来研究域上的解析函数论：边界上解析函数零点集的刻划，A无穷插值集的刻划等。

Based on wave propagating in three directions of elastic foundation, vibrating displacement could be assumed to be in three forms along three directions. Hooke's law and theory of waves were adopted to deduce the formula of coupled viscous boundary. The coupled viscous boundary could be applied in finite element method.

根据波在地基的3个方向都可以进行传播的特点，假定了地基中质点沿3个方向的振动表达式，通过胡克定律和波动理论，推导了弹性地基中三维动力问题的耦合粘性边界的公式。

Numerical experiments show that because Navier-Stokes equations at highReynolds number are a hyperbolic system,the boundary conditions are appli-cable to prescribe their boundary problems.

数值实验表明，在高Reynolds数下，由于Navier-Stokes方程呈现出很强的双曲型方程的性质，上述经过某些线性化处理得到的无反射边界条件是可以用来指定其边界值问题的。

For each potential instability mode,a critical point on the boundary of the security region was found,in which the normal vector was used to form the hyperplane to simulate the boundary of the s.

对每一种潜在的失稳模式，搜索其动态安全域边界上的一个点，根据临界点处的法向来求解用于模拟动态安全域边界的超平面。

In this thesis,the voltage stability boundary is the combined boundary which correspond to Saddle-node bifurcations and Hopf bifurcations.The closest Hopf bifurcation point is found through the proposed iterative method under the assumption that the Hopf hypersurface is continuous and convex.

因此在本论文中，在多维参数空间下，将稳定边界推广到鞍点和Hopf分岔点构成的混合稳定边界，探索性寻求Hopf分岔超平面的法向量，采用迭代算法求取系统发生最近振荡型电压失稳的负荷增长方式。

For the head-teacher of the class said that I had seriously broken the school rules,which led me to a three-day suspend class.

为什么呢？因为我的班主任说我严重的违反了校规，于是让我停课三天。

Many of them believe that the conversion of thousands of working-class folk in England spared that nation from the mass carnage and the tyranny that came with the revolution in France.

他们之中有许多人相信，在英国数以千计的劳工阶级之悔改信主使英国免於遭受如法国大革命所造成的大屠杀和专制暴政。