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排序方式: 共有254条查询结果,搜索用时 31 毫秒
31.
提出了平面弹性介质中多孔洞多裂纹相互作用问题的一种数值计算方
法. 通过把适于单一裂纹的Bueckner原理扩充到含有多孔洞多裂纹的一般体系,将原问题
分解为承受远处载荷不含裂纹不含孔洞的均匀问题,和在远处不承受载荷但在裂纹面上和孔
洞表面上承受面力的多孔洞多裂纹问题. 于是,以应力强度因子作为参量的问题可以通过考
虑后者(多孔洞多裂纹问题)来解决,而利用提出的杂交位移不连续法,这种多孔
洞多裂纹问题是容易数值求解的. 算例说明该数值方法对分析平面弹性介质中多孔洞多裂纹
相互作用的问题既简单又有效. 相似文献
32.
This paper studies the propagation of detonation and shock waves in vortex gas flows, in which the initial pressure, density, and velocity are generally functions of the coordinate — the distance from the symmetry axis. Rotational axisymmetric flow having a transverse velocity component in addition to a nonuniform longitudinal velocity is considered. The possibility of propagation of Chapman–Jouguet detonation waves in rotating flows is analyzed. A necessary conditions for the existence of a Chapman–Jouguet wave is obtained. 相似文献
33.
Semidiscrete central-upwind scheme for conservation laws with a discontinuous flux function in space
In this paper, a modified semidiscrete central-upwind scheme is derived for the scalar conservation laws with a discontinuous flux function in space. The new scheme is based on dealing with the phase transition at the stationary discontinuity, where the unknown variable function is not continuous, but the flux function is continuous. The main advantages of the new scheme are the same as them of the original semidiscrete central-upwind scheme. Numerical results are displayed to illustrate the efficiency of the methods. 相似文献
34.
35.
用精细积分法对含各向异性介质的波导不连续性问题进行了数值模拟与分析. 从矢量波动方程相对应的单变量变分形式出发, 推导出了含有各向异性介质波导横截面离散系数矩阵的表达式, 引入对偶变量, 在Hamilton体系下, 利用精细积分法求出出口刚度矩阵, 进行有限元拼装, 求解了含各向异性介质的波导不连续性问题. 算例表明了该方法的准确性和高效性. 利用本文方法还讨论了介电系数和导磁系数张量的各个分量对波导传输特性的影响.
关键词:
波导不连续性
各向异性介质
Hamilton体系
精细积分法 相似文献
36.
The Boltzmann equation which describes the time evolution of a large number of particles through the binary collision in statistics physics has close relation to the systems of fluid dynamics, that is, Euler equations and Navier-Stokes equations. As for a basic wave pattern to Euler equations, we consider the nonlinear stability of contact discontinuities to the Boltzmann equation. Even though the stability of the other two nonlinear waves, i.e., shocks and rarefaction waves has been extensively studied, there are few stability results on the contact discontinuity because unlike shock waves and rarefaction waves, its derivative has no definite sign, and decays slower than a rarefaction wave. Moreover, it behaves like a linear wave in a nonlinear setting so that its coupling with other nonlinear waves reveals a complicated interaction mechanism. Based on the new definition of contact waves to the Boltzmann equation corresponding to the contact discontinuities for the Euler equations, we succeed in obtaining the time asymptotic stability of this wave pattern with a convergence rate. In our analysis, an intrinsic dissipative mechanism associated with this profile is found and used for closing the energy estimates. 相似文献
37.
奚李群 《宁波大学学报(理工版)》1996,(2)
经典实函数理论指出:R1的一个子集合,要成为某个R1上实函数之不连续点的全体,当且仅当该集合为R1上可数个闭集的并。本文将给出进一步精细的刻画:考虑相对连续性,即指定R1的子集合A,及实函数f,对于A之导集A'中一点x0,考察f(x)是否存在,及极限是否等于f(x0),具体地,有着下述结果。设E为可数个闭集的并,R分为3个子集的不交并:R1=(E∩E')∪(E-E')∪(R-E)。那么存在R1上的有界实函数,使得1:f之不连续点的全体恰为E(与经典结果一致),2:当时,f(x)不存在,3:当时,不存在。 相似文献
38.
Summary Given a real-valued function <InlineEquation ID=IE"3"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"4"><EquationSource
Format="TEX"><![CDATA[<InlineEquation ID=IE"5"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"6"><EquationSource
Format="TEX"><![CDATA[<InlineEquation ID=IE"7"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"8"><EquationSource
Format="TEX"><![CDATA[<InlineEquation ID=IE"9"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"10"><EquationSource
Format="TEX"><![CDATA[$]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>\mu(x,y)$
of bounded variation in the sense of Hardy and Krause on the square $[0, 2\pi]\times [0, 2\pi]$, the sequence <InlineEquation
ID=IE"1"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"2"><EquationSource Format="TEX"><![CDATA[$$]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>
\mu_{m,n}:=\int^{2\pi}_0 \int^{2\pi}_0 e^{i(mx+ny)} \, d_x \, d_y \mu(x,y), \quad (m,n)\in \bZ^2, $$ may be called the sequence
of trigonometric moment constants with respect to $\mu(x,y)$. We discuss the uniqueness of the expression of the sequence
$\{\mu_{m,n}\}$ in terms of the function $\mu(x,y)$. 相似文献
39.
B. Bira 《Applicable analysis》2013,92(12):2598-2607
The aim of this paper is to carry out symmetry group analysis to obtain important classes of exact solutions from the given system of nonlinear partial differential equations (PDEs). Lie group analysis is employed to derive some exact solutions of one dimensional unsteady flow of an ideal isentropic, inviscid and perfectly conducting compressible fluid, subject to a transverse magnetic field for the magnetogasdynamics system. By using Lie group theory, the full one-parameter infinitesimal transformations group leaving the equations of motion invariant is derived. The symmetry generators are used for constructing similarity variables which leads the system of PDEs to a reduced system of ordinary differential equations; in some cases, it is possible to solve these equations exactly. Further, using the exact solution, we discuss the evolutionary behavior of weak discontinuity. 相似文献
40.
We introduce a new stochastic partial differential equation with second-order elliptic operator in divergence form, having a piecewise constant diffusion coefficient, and driven by a space–time white noise. Such equation could be used in mathematical modeling of diffusion phenomena in medium consisting of two kinds of materials and undergoing stochastic perturbations. We prove the existence of the solution and we present explicit expressions of its covariance and variance functions. Some regularity properties of the solution sample paths are also analyzed. 相似文献