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1.
Summary We study a stationary, nonlinear, particle transport problem in slab geometry with general boundary conditions. The existence and uniqueness of the solution is proved by means of fixed point techniques, provided that the source term is sufficiently small.
Sommario Si studia un problema stazionario nonlineare di particelle in geometria piana con condizioni al contorno generali. L'esistenza e unicitá della soluzione è dimostrata con tecniche di punto fisso purchè il termine di sorgente sia sufficientemente piccolo.
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I.1utroductlouWeconsidcrthenonlinearstateregulatorproblemsconsistingofthesystemontheinterval0't相似文献   

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By using the method in[3],several useful estimations of the derivatives of the solutionof the boundary value problem for a nonlinear ordinary differential equation with a turningpoint are obtained.With the help of the technique in[4],the uniform convergence on thesmall parameterεfor a difference scheme is proved.At the end of this paper,a numericalexample is given.The numerical result coincides with theoretical analysis.  相似文献   

6.
In this paper, a non-variational version of a max-min principle is proposed, andan existence and uniqueness result is obtained for the nonlinear two-point boundaryvalue problenl u"+g(t.u)=f(t),u(0)=u(2π)=0  相似文献   

7.
The problem of methane hydrate dissociation in a formation at high pressure gradients, when the flow in the near-well region is described by a nonlinear equation, is considered. In the quasistationary approximation, an analytical solution of the problem representable in the form of an implicit function is obtained. It is shown that during dissociation at high pressure gradients ice may be formed at fairly high initial temperatures. A critical diagram of hydrate dissociation regimes is plotted.  相似文献   

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A perturbation method is applied to the transport equation for a single reactive chemical with nonlinear rate loss relevant for a soil and water system. The results are compared with the linear rate loss case and the effect of different values of the perturbation parameter is shown. Exponential and step sinks modeling water withdrawn from the profile are illustrated.  相似文献   

9.
A. L. Gonor 《Fluid Dynamics》1993,28(4):468-475
A combined solution of the problem of the penetration of a compressible fluid by a slender wedge and a cone is found by the method of matched asymptotic expansions. The new solution is based on taking into account the nonlinear terms in the Cauchy-Lagrange integral and is uniformly applicable in the neighborhood of the nose.Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.4, pp. 49–57, May–June, 1993.  相似文献   

10.
This paper analyzes through Multiple Scales Method a response of a simplified nonideal and nonlinear vibrating system. Here, one verifies the interactions between the dynamics of the DC motor (excitation) and the dynamics of the foundation (spring, damper, and mass). We remarked that we consider cubic nonlinearity (spring) and quadratic nonlinearity (DC motor) of the same order of magnitude according to experimental results. Both analytical and numerical results that we have obtained had good agreement.  相似文献   

11.
The inverse problem for a class of nonlinear evolution equations of dispersive type was reduced to Cauchy problem of nonlinear evolution equation in an abstract space. By means of the semigroup method and equipping equivalent norm technique, the existence and uniqueness theorem of global solution was obtained for this class of abstract evolution equations, and was applied to the inverse problem discussed here. The existence and uniqueness theorem of global solution was given for this class of nonlinear evolution equations of dispersive type. The results extend and generalize essentially the related results of the existence and uniqueness of local solution presented by YUAN Zhong-xin. Contributed by Chen Yu-shu Foundation item: the National Natural Science Foundation of China (Significance 199990510); the National Key Basic Research Special Foundation of China (G1998020316); Liuhui Center for Applied Mathematics, Nankai University & Tianjin University Biography: Chen Fang-qi (1963-)  相似文献   

12.
IntroductionItiswell_knownthatpseudo_parabolicequationwithprincipalpartut -uxxthasbeenstudyingrecently ,becausethereexistswidephysicalbackgroundforthisclassofequations.[1 ]studiedthemulti_dimensioninverseproblemforthefollowingclassofnonlinearevolutionequ…  相似文献   

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Tomsk. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 1, pp. 106–112, January–February, 1995.  相似文献   

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Introduction Convection diffusionequationgovernssuchphenomenaastheflowofheatwithina movingfluid,thetransportofdissolvednutrientsorcontaminantswithinthegroundwater,andthetransportofasurfactantortracerwithinanincompressibleoilinapetroleum reservoir.Weconsid…  相似文献   

17.
A nonlinear reaction-diffusion equation is studied numerically by a Petrov-Galerkinfinite element method,which has been proved to be2nd-order accurate in time and4th-orderin space.The comparison between the exact and numerical solutions of progressive wavesshows that this numerical scheme is quite accurate,stable and efficient.It is also shown thatany local disturbance will spread,have a full growth and finally form two progressive wavespropagating in both directions.The shape and the speed of the long term progressive wavesare determined by the system itself,and do not depend on the details of the initial values.  相似文献   

18.
A numerical solution is presented for a nonlinear, one-dimensional boundary-value problem of thermoelasticity with variable volume force and heat supply in a half-space. The surface of the body is subjected to a given periodic displacement. The volume force and bulk heating simulate the effect of a beam of particles infiltrating the medium. No phase transition is considered and the domain of the solution excludes any shock wave formation. The basic equations are formulated in material coordinates, making them adequate for dealing with moving boundaries. The used numerical scheme reproduces correctly the process of coupled thermomechanical wave propagation. The presented figures display the process of propagation of the coupled nonlinear thermoelastic waves. They also show the effects of volume force and heat supply on the distributions of the mechanical displacements and temperature inside the medium. Moreover, the interplay between these two factors and the applied boundary disturbance is outlined. The presented solutions, however, is not meant to capture the expected process of shock formation at the breaking distance.  相似文献   

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On the basis of second-order analytical asymptotic calculations the problem of the nonlinear oscillation of a uniformly charged jet of an electrically conductive viscous fluid is solved with account for the radial fluid velocity distribution in the jet. It is found that energy from the initially excited wave is gradually transmitted to a wave with double the wave number excited due to nonlinear interaction in the viscous jet, whereas in an ideal fluid the nonlinear correction amplitude is formed instantaneously at the initial instant.  相似文献   

20.
In this paper,a nonlinear,unsteady3-D free surface problem of the oblique water exitof an axisymmetric body with a large water exit-angle was investigated by means of theperturbation method in which the complementary angle a of the water exit angle waschosen as a small parameter.The original3-D problem was solved by expanding it into apower series of a and reduced to a number of2-D problems.The integral expressions forthe first three order solutions were given in terms of the complete elliptic functions of thefirst and second kinds.The zeroth-order solution didn‘t turn out to be a linear problem asusual but a nonlinear one corresponding to the vertical water exit for the same body.Computational results were presented for the free surface shapes and the forces exerted upto the second order during the oblique water exit of a series of ellipsoids with various ratiosof length to diameter at different Froude numbers.  相似文献   

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