共查询到20条相似文献,搜索用时 31 毫秒
1.
V. M. Mirsalimov 《Fluid Dynamics》2011,46(2):262-269
The two-dimensional problem with an unknown boundary of the development of a periodic system of cavities in viscous bodies
under finite deformations is considered. The solution of the periodic problem of the development of a system of similar cavities
in a slow time-dependent flow of a Newtonian viscous fluid is derived. 相似文献
2.
The investigation of flow in essentially inhomogeneous porous systems through the analysis of model periodic structures [1] is considered. In the acoustic approximation, an integrodifferential equation is obtained that describes the motion of a viscous fluid in a rigid porous medium of periodic structure. The velocity vector and pressure are represented in the form of asymptotic series with respect to a small parameter that characterizes the size of the periodicity cell, and the well-known procedure for averaging linearized hydrodynamic equations with small coefficients of viscosity [2, 3] is also used. A solution is presented to the local problem in the periodicity cell for a structure consisting of a doubly periodic system of infinitely long rods of circular section and a compressible viscous fluid that fills the space between them, and also for a structure formed by a system of orthogonal rectilinear channels, filled with viscous fluid, in a solid.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 123–130, March–April, 1988. 相似文献
3.
Propagation of Harmonic Waves Through Fibrous and Porous Elastic Materials of Regular Microstructure
V. T. Golovchan 《International Applied Mechanics》2002,38(10):1178-1200
A presentation is made of the findings on the propagation of free waves through elastic media with a row of evenly spaced cylindrical cavities. To solve the arising boundary-value problems, the strict method proposed earlier by the author is used. Antiplane elastic problems are studied for domains in the form of a plane-parallel layer, a half-space, a space with one infinite row of cylindrical cavities, and a space with a doubly periodic system of cavities. The calculated roots of the dispersion determinant are tabulated. A detailed analysis of the wave field is carried out. The method used is demonstrated to be highly efficient. 相似文献
4.
双周期圆柱形夹杂纵向剪切问题的精确解 总被引:7,自引:1,他引:7
研究无限介质中矩形排列双周期圆柱形夹杂的纵向剪切问题.利用Eshelby等效夹杂理论并结合双周期与双准周期解析函数工具,为这类考虑夹杂相互影响的问题提供了一个严格又实用的分析方法,求得了问题的全场级数解.作为退化情形得到单夹杂问题的经典解答,双周期孔洞、双周期刚性夹杂及单行(列)周期弹性夹杂等问题也可作为特殊情况被解决.数值结果揭示了这类非均匀材料力学性质随微结构参数变化的规律. 相似文献
5.
6.
This paper studies existence of at least three positive doubly periodic solutions of a coupled nonlinear telegraph system with doubly periodic boundary conditions. First, by using the Green function and maximum principle, existence of solutions of a nonlinear telegraph system is equivalent to existence of fixed points of an operator. By imposing growth conditions on the nonlinearities, existence of at least three fixed points in cone is obtained by using the Leggett-Williams fixed point theorem to cones in ordered Banach spaces. In other words, there exist at least three positive doubly periodic solutions of nonlinear telegraph system. 相似文献
7.
A. M. Pylaev 《Fluid Dynamics》2005,40(3):349-358
The results of an analysis of the linear perturbations of equilibrium of a viscous heat-conducting fluid or gas in cavities with simple geometric cross-sections are given. Both plane motions and motions periodic in the direction of the horizontal generator of the boundary surface are considered. Variants in which the acceleration of the mass force field can be both constant and periodically modulated are calculated. The solutions of the problem for the stream function (or the vertical velocity component) and the temperature are represented in the form of double or triple Fourier series. For the coefficients in the expansions an infinite system of equations which admits reduction is obtained. The results are found to be in good agreement with the known data.__________Translated from Izvestiya Rossiiskoi Academii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, 2005, pp. 14–24.Original Russian Text Copyright © 2005 by Pylaev. 相似文献
8.
双周期圆截面纤维复合材料平面问题的解析法 总被引:4,自引:0,他引:4
结合双准周期Riemann边值问题理论与Eshelby等效夹杂原理,为双周期圆截面纤维复合材
料平面问题发展了一个实用有效的解析方法,获得了问题的全场级数解并与有限元结果进行
了比较. 该方法为非均匀材料的力学性质分析和复合材料等新材料的微结构设计提供了
一个有效的计算工具,也可用来评估有限元等数值与近似方法的精度. 相似文献
9.
F. A. Bakhyshov V. M. Mirsalimov 《Journal of Applied Mechanics and Technical Physics》2006,47(4):588-595
Based on the balanced strength principle, a problem of determining the optimal interference for fitting elastic inclusions
into holes of an isotropic elastic plate weakened by a doubly periodic system of circular holes is solved. A closed system
of algebraic equations is derived, which allows solving this problem. The resultant interference increases the load-carrying
capacity of the composite plate being bent.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 4, pp. 153–161, July–August, 2006. 相似文献
10.
We consider the full Navier–Stokes–Fourier system describing the motion of a compressible viscous and heat conducting fluid
driven by a time-periodic external force. We show the existence of at least one weak time periodic solution to the problem
under the basic hypothesis that the system is allowed to dissipate the thermal energy through the boundary. Such a condition
is in fact necessary, as energetically closed fluid systems do not possess non-trivial (changing in time) periodic solutions
as a direct consequence of the Second law of thermodynamics. 相似文献
11.
A system of integral equations of the boundary element method for studying doubly periodic systems of thin inclusions in anisotropic bodies is constructed. Several dependences for determining the mean stresses and strains of a composite with regular systems of thin inhomogeneities are obtained. Numerical procedures of the proposed method are implemented, and generalized stress intensity factors are calculated together with the effective elasticity moduli of a composite with doubly periodic systems of thin elastic inclusions. 相似文献
12.
Mark A. Stremler 《Theoretical and Computational Fluid Dynamics》2010,24(1-4):25-37
The motion of two point vortices defines an integrable Hamiltonian dynamical system in either singly or doubly periodic domains. The motion of three point vortices in these domains is also integrable when the net circulation is zero. The relative vortex motion in both domains can be reduced to advection of a passive particle by fixed vortices in an equivalent Hamiltonian system. A survey of the solutions for vortex motion in these systems is discussed. Some initial conditions lead to relative equilibria, or vortex configurations that move without change of shape or size. These configurations can be determined as stagnation points in the reduced problem or through explicit solution of the governing equations. These periodic point-vortex systems present a rich collection of interesting solutions despite the few degrees of freedom, and several questions on this subject remain open. 相似文献
13.
E. S. Shalimova 《Moscow University Mechanics Bulletin》2014,69(4):89-96
The problem of motion of a heavy material point on a sphere uniformly rotating about a fixed axis is considered in the case of viscous friction. The angle of inclination between the axis and the horizon is constant. The existence, bifurcation, and stability of the equilibrium positions are discussed for such a mechanical system. The existence of periodic motions is also studied. An approach is proposed to find such motions in the case of low viscosity. 相似文献
14.
研究无限压电介质中双周期圆柱形压电夹杂的反平面问题.借鉴Eshelby等效夹杂原理,通过引入双周期非均匀本征应变和本征电场,构造了一个与原问题等价的均匀介质双周期本征应变和本征电场问题.利用双准周期Riemann边值问题理论,获得了夹杂内外严格的电弹性解.作为压电纤维复合材料的一个重要模型,预测了压电纤维复合材料的有效电弹性模量. 相似文献
15.
《International Journal of Solids and Structures》2002,39(23):5837-5850
A unique scalar parameter arises in the 3-D homogenization model for the beam bundle, which has the significance of the added fluid area fraction. The parameter is determined by solving a local problem defined on a unit cell, and its relation to the porosity of the bundle is investigated in this paper. This is made possible by obtaining an analytical solution of the local problem based on Weierstrass’s doubly periodic functions. 相似文献
16.
An asymptotic solution of the problem of time evolution of a periodic wave on the surface of a viscous, infinitely deep fluid in the approximation quadratic in the wave amplitude is proposed. 相似文献
17.
The results of an experimental and numerical investigation of the flow in an axisymmetric channel with radial cavities are presented. The experiments were performed with air in a wind tunnel. The theoretical results obtained by numerically solving the problem of viscous axisymmetric gas flow agree with the experimental data on the longitudinal velocity profiles in a channel with a radial cavity. 相似文献
18.
This Note is devoted to the analysis of elastic waves conically propagating through a doubly periodic array of cylindrical channels. A new method, based on a multiple scattering approach, has been proposed to reduce the problem to an algebraic system of the Rayleigh type. We obtain an eigenvalue problem formulation that enables us to construct the high-order dispersion curves and to study phononic band gap structures in oblique propagation. We note an effect of singular perturbation associated with a small angle of conical propagation. To cite this article: S. Guenneau et al., C. R. Mecanique 330 (2002) 491–497. 相似文献
19.
V. G. Baidulov 《Fluid Dynamics》2010,45(6):835-842
The stability of boundary flows occurring near an inclined plane or a cylinder executing longitudinal periodic oscillations
is studied within the framework of a system of embedded models (homogeneous fluid, stratified viscous fluid, and fluid in
the presence of diffusion). It is shown that in a stratified fluid the resonance boundary-oscillation frequency, at which
the boundary layer thickness increases without bound, exists not only in the problem with a plane boundary but also in the
case of oscillations of an inclined cylinder. Taking diffusion into account leads to the boundary layer splitting into viscous
and diffusion sublayers with considerably different thicknesses and properties. Nevertheless, the fact itself of the existence
of the resonance oscillation frequency turns out to be stable and the resonance takes place also in the models of stratified
flows with allowance for diffusion. 相似文献
20.
G. V. Kuznetsov A. V. Krainov 《Journal of Applied Mechanics and Technical Physics》2001,42(5):851-856
Numerical simulation was performed of the motion of a viscous incompressible nonisothermal fluid in an open rectangular cavity under conditions of forced convection and conjugate heat exchange. The effect of the jet dynamic parameter (Reynolds number) and fluid flow conditions on the character of motion and heat exchange of viscous incompressible nonisothermal fluids in rectangular cavities is studied. A hydrodynamic pattern of viscous flow in an open cavity under forced convection conditions (in the conjugate and nonconjugate formulations of the problem) is obtained. The effect of parameters of the model on the character of motion is studied. Temperature profiles for the solid and fluid phases are obtained. The effect of parameters of the model on the character of temperature distribution in both phases is studied. 相似文献