共查询到20条相似文献,搜索用时 15 毫秒
1.
V. V. Zalipaev 《Journal of Mathematical Sciences》2000,102(4):4195-4202
In the present paper, the high-frequency diffraction of a plane wave by a right-angle step discontinuity in an impedance plane
is analyzed with the help of the uniform geometric theory of diffraction, beginning with the Maluzhenets solution. The principal
term of an asymptotic solution of the problem, which is uniform with respect to the angle of incidence of the plane wave and
the angle of observation, is derived. The excitation of primary and multiply diffracted fields radiated from the upper edge,
as well as surface waves, is considered (the lower edge does not radiate cylindrical or surface waves owing to a right-angle
step). For simplicity, the details of computation are given here for a right-angle step discontinuity. A similar procedure
is applied to other examples with more complicated geometry. Bibliography: 7 titles.
Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 250, 1998, pp. 97–108.
Translated by V. V. Zalipaev. 相似文献
2.
《Journal of Applied Mathematics and Mechanics》2006,70(4):590-598
The reflection and refraction of a plane acoustic wave by a thermoelastic plane layer, non-uniform in thickness, bounded by non-viscous heat-conducting liquids, generally different, is considered. The system of equations for small perturbations of the thermoelastic medium is reduced to a system of ordinary differential equations, the boundary-value problem for which is solved by two methods: the spline-collocation method and the power-series method. Analytic expressions are obtained which describe the wave fields outside the layer. The results of calculations of the intensity transmission coefficient of the acoustic wave are presented. 相似文献
3.
We study small holes through which regular 3-, 4-, and 5-dimensional simplices can pass. 相似文献
4.
This paper addresses the computation of the three-dimensional transient heat transfer through a layered solid and/or fluid formation containing irregular inclusions. The use of appropriate Green’s functions for a flat layer formation in a boundary element method formulation avoids the discretization of the layer interface boundaries. 相似文献
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6.
A. A. Lokshin 《Journal of Applied Mathematics and Mechanics》1994,58(6):1111-1114
Exact formulae are derived for the reflected and refracted waves which occur for the inclined incidence of a plane horizontally polarized transverse wave of arbitrary profile on a horizontal interface between two elastic half-spaces experiencing non-linear friction when they move with respect to one another. A smooth function of general form is adopted as the friction function, which depends on the difference between the horizontal velocities of the elements of the boundaries of the half-spaces considered. It is shown that if the friction function depends non-monotonically on the relative velocity of displacement of the sides of a slit, then even when the profile of the incident wave is smooth, the reflected and refracted waves may contain strong discontinuities. 相似文献
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8.
Hong Wang 《Journal of Graph Theory》1997,26(2):105-109
We propose a conjecture: for each integer k ≥ 2, there exists N(k) such that if G is a graph of order n ≥ N(k) and d(x) + d(y) ≥ n + 2k - 2 for each pair of non-adjacent vertices x and y of G, then for any k independent edges e1, …, ek of G, there exist k vertex-disjoint cycles C1, …, Ck in G such that ei ∈ E(Ci) for all i ∈ {1, …, k} and V(C1 ∪ ···∪ Ck) = V(G). If this conjecture is true, the condition on the degrees of G is sharp. We prove this conjecture for the case k = 2 in the paper. © 1997 John Wiley & Sons, Inc. J Graph Theory 26: 105–109, 1997 相似文献
9.
Jürgen Socolowsky 《PAMM》2007,7(1):2100033-2100034
An evolutionary problem on the viscous (isothermal) flow of two connected fluids down an inclined plane is investigated. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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I. V. Kamotskii 《Journal of Mathematical Sciences》1998,91(2):2748-2756
The problem of scattering on a periodic curve is considered. The asymptotic solution of the problem is constructed, and its
principal terms are presented. The justification of the asymptotic solution found is provided. Bibliography: 7 titles.
Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 230, 1995, pp. 75–85.
Translated by I. V. Kamotskii 相似文献
13.
T. Robert Faulkner 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1966,17(6):699-707
Zusammenfassung Das Problem der Beugung einer Oberflächenwelle, die schief auf ein völlig versenktes, ebenes Hindernis stösst, wobei das ebene Hindernis senkrecht zur ruhenden Oberfläche steht, wird auf die Lösung der Helmholtz-Gleichung reduziert. Die Lösung wird nach dem Wiener-Hopf-Verfahren durchgeführt und ergibt die Reflexionsbeiwerte. 相似文献
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15.
M. A. Lyalinov 《Journal of Mathematical Sciences》2010,167(5):651-659
Diffraction of a plane wave by a circular impedance cone is studied. Surface waves propagating from the vertex of the cone
are discussed. The excitation coefficient is computed with the help of the incomplete separation of variables in the problem.
Bibliography: 14 titles. 相似文献
16.
Gordon C. K. Yeh 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1964,15(3):237-252
Zusammenfassung Ein sphärischer Hohlraum in einem unendlichen homogenen und isotropen elastischen Medium wird von einer ebenen Druckstosswelle überstrichen, deren Front sich gleichförmig fortbewegt. Das durch Ablenkung am Hohlraum erzeugte Verschiebungs- und spannungsfeld wird mittels einer Integraltransformation bestimmt. Insbesondere wird die starre Teilbewegung der Begrenzung des Hohlraums ermittelt. Das Problem wird für eine einstufige Druckwelle gelöst. Die Ergebnisse lassen sich als Einflussgrössen betrachten, mit denen sich die Duhamel-Integrale für allgemeinere Druckwellen berechnen lassen.
This work was performed under Contract No. AF 29(601)-5132 (Project No. 1080, Task No. 108007) for Air Force Special Weapons Center, Kirtland Air Force Base, New Mexico, USA. 相似文献
This work was performed under Contract No. AF 29(601)-5132 (Project No. 1080, Task No. 108007) for Air Force Special Weapons Center, Kirtland Air Force Base, New Mexico, USA. 相似文献
17.
The problem of diffraction of a plane scalar wave by a narrow cone is considered. The shape of the cone is arbitrary. The
boundary condition is the Dirichlet or Neumann one. The wave scattered by the cone vertex arises as a result of the diffraction
process. The subject of this paper is to calculate the wave amplitude. If the cone is narrow, it is possible to obtain simpler
approximate formulas in comparison with Smyshlayev's one. The exactness of the approximate formulas is checked numerically.
The etalon is a solution in explicit form in the axially symmetric case. The calculation shows that our formula is more exact
in the case of the Dirichlet boundary condition than Felsen's formula. The approximate formula is a generalization of Felsen's
one for circular cone to an arbitrary narrow cone in the case of the Neumann boundary condition. Bibliography: 6 titles.
Dedicated to N. N. Uraltseva on her jubilee
Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 221, 1995, pp. 67–74.
Translated by D. B. Dement'ev. 相似文献
18.
Kazuhide Hirohata 《Journal of Graph Theory》1998,29(3):177-184
For a graph G and an integer k ≥ 1, let ςk(G) = dG(vi): {v1, …, vk} is an independent set of vertices in G}. Enomoto proved the following theorem. Let s ≥ 1 and let G be a (s + 2)-connected graph. Then G has a cycle of length ≥ min{|V(G)|, ς2(G) − s} passing through any path of length s. We generalize this result as follows. Let k ≥ 3 and s ≥ 1 and let G be a (k + s − 1)-connected graph. Then G has a cycle of length ≥ min{|V(G)|, − s} passing through any path of length s. © 1998 John Wiley & Sons, Inc. J. Graph Theory 29: 177–184, 1998 相似文献
19.
Peter Wolfe 《Journal of Mathematical Analysis and Applications》1979,67(1):35-57
In this paper we solve the problem of diffraction of a normally incident plane wave by a circular disk. We treat both the hard and soft disk. In each case we obtain the solution as a series which converges when the product of the wave number and the radius of the disk is large. Our construction leads directly to asymptotic approximations to the solution for large wave number. 相似文献
20.
Numerical methods are proposed for solving problems of diffraction of a plane electromagnetic wave on a nonhomogeneous interface of two media. Strictly periodic cylindrical surfaces are considered, as well as surfaces that are nonplanar on a finite section. Algorithms are developed for computing the characteristics of the reflected field in the far zone. Numerical results are reported for various electrodynamic models, and their limits of applicability are investigated.Translated from Matematicheskie Modeli Estestvoznaniya, Published by Moscow University, Moscow, 1995, pp. 86–111. 相似文献