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本文讨论了一个角形区域上边界条件有间断点的Laplace方程混合边值问题 的适定性,并给出了完整的解答. 相似文献
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<正> 在L.Bers和L.Nirenberg的文[1]中,研究了一定条件下的二阶非线性一致椭圆型方程 Φ(x,y,u,u_x,u_y,u_(xx),u_(xy),u_(yy))=0(1.1)于单连通区域上的Dirichlet边值问题与Neumann边值问题解的存在性.近几年来,我们也曾对二阶非线性一致椭圓型方程的复形式讨论过解的一些性质与平面多连通区域D上的第一、二、三边值问题与混合边值问题的可 相似文献
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本文结合差分方法与边界积分方程方法,提出并研究了一类新的求解发展型方程初边值问题的高阶差分与边界积分方程耦合数值方法.对于有界区域问题与无界区域问题给出了数值计算格式及其误差的先验估计. 相似文献
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Helmholtz方程外边值问题的自然边界元法 总被引:6,自引:0,他引:6
李瑞遐 《高校应用数学学报(A辑)》1997,(3):369-374
本文利用Fourier展开获得了圆外区域上的Helmholtz方程边值问题的Poisson积分公式和积分方程,并用Galerkin法求积分方程的解,导出了刚度矩阵元素的计算公式,讨论了数值技术,给出了变分解的唯一性定理和近似解的误差估计。 相似文献
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利用 Laray-Schauder 不动点原理研究拟线性椭园型方程,得到了较完善的结果。[1]作了极好的总结。但证明比较繁复。而[2]仅用各向同性连续函数空间的内插不等式,给出了半线性椭园型方程解的存在性和可微性的简单证明。本文引进了各向异性连续函数空间 C~(k a)·(k a)/2,证明了此空间的内插不等式,并用来解决了半线性抛物型方程第一边值问题,斜导数问题及方程组一般边值问题解的存在 相似文献
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<正> 本文讨论一般椭圆型方程的非局部边值问题.这类非局部边值问题与F.E.Browder,M.Schechter,J.L.Lions,E.Magenes等人所讨论的非局部边值问题不同.一般情形下,对于2m阶方程需要给出2m个非局部边界条件,从某种意义上来说要更“非局部”一些.我们在[4]中讨论的二阶自共轭椭圓型方程与重调和方程的互补边值问题就是 相似文献
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Bo JiangXuehou Tan 《Discrete Applied Mathematics》2011,159(16):1793-1805
We consider the problem of searching for a mobile intruder in a circular corridor by two mobile searchers, who hold one flashlight. A circular corridor is a polygon with one polygonal hole such that its outer and inner boundaries are mutually weakly visible. Both 1-searchers always direct their flashlights at the inner boundary. The objective is to decide whether there exists a search schedule for two 1-searchers to detect the intruder, no matter how fast he moves, and if so, generate a search schedule. We give a characterization of the circular corridors, which are searchable by two 1-searchers. Based on our characterization, an O(nlogn) time algorithm is then presented to determine the searchability of a circular corridor, where n denotes the total number of vertices of the outer and inner boundaries. Moreover, a search schedule can be reported in time linear in its size, if it exists. 相似文献
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In this paper we propose a numerical scheme for treating the problem of sJow viscous flow past an obstacle in the plane. This scheme is a combination of boundary element and finite element methods. By introducing an auxiliary boundary curve, we divide the region under consideration into two subregions, an inner and an outer region. In the inner region, we employ a finite element method (FEM) for solving a system of simplified field equations with proper natural boundary conditions. In the outer region, the solution is expressed in the form of a simple-layer potential with density function satisfying a system of modified integral equations of the first kind. The latter are solved by a boundary element method (BEM). Both solutions are matched on the common auxiliary boundary curve. Error estimates in suitable function spaces are derived in terms of the mesh widths as well as the small parameters, the Reynolds numbers 相似文献
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双重介质分形油藏渗流问题 总被引:4,自引:0,他引:4
将油井有效半径引入双重介质分形油藏渗流问题的内边界之中,从而建立了双重介质分形油藏的一种渗流模型,并在考虑了井筒储集和表皮效应的情况求得了外边界为无限大、有界封闭和有界定压三种情况下双重介质分形油藏压力分布的精确解析表达式,利用拉氏数值反演Stehfest方法分析了双重介质分形油藏压力动态特征,讨论了各种参数对压力动态的影响。 相似文献
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在详细分析线性流量阀工作原理的基础上,应用平面解析几何、微积分等相关概念,给出了不存在呈严格线性的流量阀的数学论证.在设计近似线性流量阀时,首先构造了"线性误差函数"用以刻画"过流面积"与角度之间的线性误差.之后在分析内孔为对称直线、对称1/2次曲线的基础上,设计出内孔为倒"S"形内孔曲线图,通过最小化线性误差函数,得到内孔曲线的最佳参数.最后针对外孔有磨损时,给出了设计方案. 相似文献
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In this article, the perimeter detection optimization problem in field surveillance and target tracking are discussed. The detection range of sensors is assumed to be circular or elliptical. Sensors are also assumed to be associated with a cost factor reflecting their operational characteristics and power usage. We show that the problem of optimal sensor selection can be reduced to a network flow problem and can then be solved using any existing classical methodology. This significantly reduces the computational time of sensory selection problem which in many cases needs to be solved in almost real time basis, every time that the dynamics of the field changes. The field dynamics could change due to such events as wind direction change and sensor failures. 相似文献
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J. Giroire T. Ha‐Duong V. Moumas 《Mathematical Methods in the Applied Sciences》2005,28(13):1527-1552
This article deals with a boundary value problem for Laplace equation with a non‐linear and non‐local boundary condition. This problem comes from petroleum engineering and is used to obtain an estimation of well productivity. The non‐linear and non‐local boundary condition is written on the well boundary. On the outer reservoir boundaries, we have both Dirichlet and Neumann conditions. In this paper, we prove the existence and uniqueness of a solution to this problem. The existence is proved by Schauder theorem and the uniqueness is obtained under more restricted conditions, when the involved operator is a contraction. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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本文研究无穷凹角区域上一类各向异性问题的自然边界元与有限元耦合法.利用自然边界归化原理,获得圆弧或椭圆弧人工边界上的自然积分方程,给出了耦合的变分形式及其数值方法,以及逼近解的收敛性和误差估计,最后给出了数值例子,以示方法的可行性和有效性. 相似文献
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This paper presents an analytical solution to estimate the liquid film thickness in two-phase annular flow through a circular pipe using electrical resistance tomography. Gas–liquid flow with circular gas core surrounded by a liquid film is considered. Conformal mapping is employed to obtain the analytic solution for annular flow with an eccentric circular gas core. The liquid film thickness for an arbitrary annular flow is estimated by comparing the resistance values for concentric and eccentric annular flows. The film thickness estimation has a good performance when the normalized distance between the gas core center and the flow center is less than 0.2 and the void fraction is greater than 0.4, the estimated error of the normalized thickness is less than 0.04. 相似文献