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Approximate solutions of the Alekseevskii–Tate model of long-rod penetration 被引量:6
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作者 W.J.Jiao X.W.Chen 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2018年第2期334-348,共15页
The Alekseevskii–Tate model is the most successful semi-hydrodynamic model applied to long-rod penetration into semi-infinite targets. However, due to the nonlinear nature of the equations, the rod(tail) velocity, pe... The Alekseevskii–Tate model is the most successful semi-hydrodynamic model applied to long-rod penetration into semi-infinite targets. However, due to the nonlinear nature of the equations, the rod(tail) velocity, penetration velocity, rod length, and penetration depth were obtained implicitly as a function of time and solved numerically By employing a linear approximation to the logarithmic relative rod length, we obtain two sets of explicit approximate algebraic solutions based on the implicit theoretica solution deduced from primitive equations. It is very convenient in the theoretical prediction of the Alekseevskii–Tate model to apply these simple algebraic solutions. In particular, approximate solution 1 shows good agreement with the theoretical(exact) solution, and the first-order perturbation solution obtained by Walters et al.(Int. J. Impac Eng. 33:837–846, 2006) can be deemed as a special form of approximate solution 1 in high-speed penetration. Meanwhile, with constant tail velocity and penetration velocity approximate solution 2 has very simple expressions, which is applicable for the qualitative analysis of long-rod penetration. Differences among these two approximate solutions and the theoretical(exact) solution and their respective scopes of application have been discussed, and the inferences with clear physical basis have been drawn. In addition, these two solutions and the first-order perturbation solution are applied to two cases with different initial impact velocity and different penetrator/target combinations to compare with the theoretical(exact) solution. Approximate solution 1 is much closer to the theoretical solution of the Alekseevskii–Tate model than the first-order perturbation solution in both cases, whilst approximate solution 2 brings us a more intuitive understanding of quasi-steady-state penetration. 展开更多
关键词 Long-rod penetration Alekseevskii–Tate model Theoretical solution approximate solution Perturbation solution
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Dynamic characteristics of resonant gyroscopes study based on the Mathieu equation approximate solution 被引量:2
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作者 樊尚春 李艳 +2 位作者 郭占社 李晶 庄海涵 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第5期58-65,共8页
Dynamic characteristics of the resonant gyroscope are studied based on the Mathieu equation approximate solution in this paper.The Mathieu equation is used to analyze the parametric resonant characteristics and the ap... Dynamic characteristics of the resonant gyroscope are studied based on the Mathieu equation approximate solution in this paper.The Mathieu equation is used to analyze the parametric resonant characteristics and the approximate output of the resonant gyroscope.The method of small parameter perturbation is used to analyze the approximate solution of the Mathieu equation.The theoretical analysis and the numerical simulations show that the approximate solution of the Mathieu equation is close to the dynamic output characteristics of the resonant gyroscope.The experimental analysis shows that the theoretical curve and the experimental data processing results coincide perfectly,which means that the approximate solution of the Mathieu equation can present the dynamic output characteristic of the resonant gyroscope.The theoretical approach and the experimental results of the Mathieu equation approximate solution are obtained,which provides a reference for the robust design of the resonant gyroscope. 展开更多
关键词 resonant gyroscopes dynamic characteristics Mathieu equation approximate solution
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Approximate Solution for Mechanism of Thermally and Wind-driven Ocean Circulation 被引量:4
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作者 MO Jiaqi LIN Wantao LIN Yihua 《Chinese Geographical Science》 SCIE CSCD 2010年第5期383-388,共6页
The thermally and wind-driven ocean circulation is a complicated natural phenomenon in the atmospheric physics. Hence we need to reduce it using basic models and solve the models using approximate methods. A non-linea... The thermally and wind-driven ocean circulation is a complicated natural phenomenon in the atmospheric physics. Hence we need to reduce it using basic models and solve the models using approximate methods. A non-linear model of the thermally and wind-driven ocean circulation is used in this paper. The results show that the zero solution of the linear equation is a stable focus point, which is the path curve trend origin point as time (t) trend to infinity. By using the homotopic mapping perturbation method, the exact solution of the model is obtained. The homotopic mapping perturbation method is an analytic solving method, so the obtained solution can be used for analytic operating sequentially. And then we can also obtain the diversified qualitative and quantitative behaviors for corresponding physical quantities. 展开更多
关键词 global climate atmosphere-ocean oscillation homotopic mapping approximate solution
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Approximate Analytic Solution of Solitary Wave for a Class of Nonlinear Disturbed Long-Wave System 被引量:5
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作者 莫嘉琪 姚静荪 唐荣荣 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第7期27-30,共4页
In this paper, the approximate expressions of the solitary wave solutions for a class of nonlinear disturbed long-wave system are constructed using the homotopie mapping method.
关键词 nonlinear long-wave equation solitary wave approximate analytic solution
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Classification and Approximate Solutions to Perturbed Nonlinear Diffusion-Convection Equations 被引量:2
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作者 WANG Yong ZHANG Shun-Li 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第1期17-21,共5页
This paper studies the perturbed nonlinear diffusion-convection equation with source term via the approximate generalized conditional symmetry (A GCS). Complete classification of those perturbed equations which admi... This paper studies the perturbed nonlinear diffusion-convection equation with source term via the approximate generalized conditional symmetry (A GCS). Complete classification of those perturbed equations which admit certain types of AGCSs is derived. Some approximate invariant solutions to the resulting equations can also be obtained. 展开更多
关键词 perturbed nonlinear diffusion-convection equation approximate generalized conditional symme-try approximate invariant solution
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STRONG COMPACTNESS OF APPROXIMATE SOLUTIONS TO DEGENERATE ELLIPTIC-HYPERBOLIC EQUATIONS WITH DISCONTINUOUS FLUX FUNCTION 被引量:1
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作者 Helge Holden Kenneth H. Karlsen +1 位作者 Darko Mitrovic Evgueni Yu. Panov 《Acta Mathematica Scientia》 SCIE CSCD 2009年第6期1573-1612,共40页
Under a non-degeneracy condition on the nonlinearities we show that sequences of approximate entropy solutions of mixed elliptic-hyperbolic equations are strongly precompact in the general case of a Caratheodory flux ... Under a non-degeneracy condition on the nonlinearities we show that sequences of approximate entropy solutions of mixed elliptic-hyperbolic equations are strongly precompact in the general case of a Caratheodory flux vector. The proofs are based on deriving localization principles for H-measures associated to sequences of measurevalued functions. This main result implies existence of solutions to degenerate parabolic convection-diffusion equations with discontinuous flux. Moreover, it provides a framework in which one can prove convergence of various types of approximate solutions, such as those generated by the vanishing viscosity method and numerical schemes. 展开更多
关键词 degenerate hyperbolic-elliptic equation degenerate convection-diffusion equation conservation law discontinuous flux approximate solutions COMPACTNESS
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Approximate solution for the Klein Gordon-Schrdinger equation by the homotopy analysis method 被引量:1
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作者 王佳 李彪 叶望川 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第3期83-89,共7页
The Homotopy analysis method is applied to obtain the approximate solution of the Klein-Gordon Schrodinger equation. The Homotopy analysis solutions of the Klein-Gordon Schrodinger equation contain an auxiliary parame... The Homotopy analysis method is applied to obtain the approximate solution of the Klein-Gordon Schrodinger equation. The Homotopy analysis solutions of the Klein-Gordon Schrodinger equation contain an auxiliary parameter which provides a convenient way to control the convergence region and rate of the series solutions. Through errors analysis and numerical simulation, we can see the approximate solution is very close to the exact solution. 展开更多
关键词 Klein-Gordon-Schrodinger equation homotopy analysis method approximate solution
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New approximate solution for time-fractional coupled KdV equations by generalised differential transform method 被引量:1
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作者 刘金存 侯国林 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第11期41-47,共7页
In this paper, the genera]ised two-dimensiona] differentia] transform method (DTM) of solving the time-fractiona] coupled KdV equations is proposed. The fractional derivative is described in the Caputo sense. The pr... In this paper, the genera]ised two-dimensiona] differentia] transform method (DTM) of solving the time-fractiona] coupled KdV equations is proposed. The fractional derivative is described in the Caputo sense. The presented method is a numerical method based on the generalised Taylor series expansion which constructs an analytical solution in the form of a polynomial. An illustrative example shows that the genera]ised two-dimensional DTM is effective for the coupled equations. 展开更多
关键词 fractional coupled KdV equations Caputo fractional derivative differential transform method approximate analytic solution
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Approximate Symmetries and Infinite Series Symmetry Reduction Solutions to Perturbed Kuramoto-Sivashinsky Equation 被引量:2
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作者 YAO Ruo-Xia JIAO Xiao-Yu LOU Sen-Yue 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第5期785-788,共4页
Starting from Lie symmetry theory and combining with the approximate symmetry method, and using the package LieSYMGRP proposed by us, we restudy the perturbed Kuramoto-Sivashinsky (KS) equation. The approximate symm... Starting from Lie symmetry theory and combining with the approximate symmetry method, and using the package LieSYMGRP proposed by us, we restudy the perturbed Kuramoto-Sivashinsky (KS) equation. The approximate symmetry reduction and the infinite series symmetry reduction solutions of the perturbed KS equation are constructed. Specially, if selecting the tanh-type travelling wave solution as initial approximate, we not only obtain the general formula of the physical approximate similarity solutions, but also obtain several new explicit solutions of the given equation, which are first reported here. 展开更多
关键词 perturbed Kuramoto-Sivashinsky equation approximate symmetry reduction series reduction solution
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Classification and Approximate Solutions to a Class of Perturbed Nonlinear Wave Equations 被引量:1
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作者 ZHANG Zhi-Yong CHEN Yu-Fu YONG Xue-Lin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第11期769-772,共4页
A complete approximate symmetry classification of a class of perturbed nonlinear wave equations isperformed using the method originated from Fushchich and Shtelen.Moreover,large classes of approximate invariantsolutio... A complete approximate symmetry classification of a class of perturbed nonlinear wave equations isperformed using the method originated from Fushchich and Shtelen.Moreover,large classes of approximate invariantsolutions of the equations based on the Lie group method are constructed. 展开更多
关键词 approximate symmetry Lie reduction approximate solution
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Approximate Analytical Solutions for Scattering States of D-dimensional Hulthen Potentials 被引量:1
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作者 CHEN Chang-Yuan SUN Dong-Sheng LIU Cheng-Lin LU Fa-Lin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第3期399-404,共6页
Using the exponential function transformation approach along with an approximation for the centrifugal potential, the radial Schr6dinger equation of D-dimensional Hulthen potential is transformed to a hypergeometric d... Using the exponential function transformation approach along with an approximation for the centrifugal potential, the radial Schr6dinger equation of D-dimensional Hulthen potential is transformed to a hypergeometric differential equation. The approximate analytical solutions of scattering states are attained. The normalized wave functions expressed in terms of hypergeometrie functions of scattering states on the "k/2π scale" and the calculation formula of phase shifts are given. The physical meaning of the approximate analytical solutions is discussed. 展开更多
关键词 D-dimensional Hulthen potential Schrodinger equation scattering states approximate analytical solutions
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Approximate Relativistic Solutions for One-Dimensional Cylindrical Coaxial Diode 被引量:1
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作者 曾正中 刘国治 邵浩 《Plasma Science and Technology》 SCIE EI CAS CSCD 2002年第1期1093-1100,共8页
Two approximate analytical relativistic solutions for one-dimensional, space-charge- limited cylindrical coaxial diode are derived and utilized to compose best-fitting approximate solutions. Comparison of the best-fit... Two approximate analytical relativistic solutions for one-dimensional, space-charge- limited cylindrical coaxial diode are derived and utilized to compose best-fitting approximate solutions. Comparison of the best-fitting solutions with the numerical one demonstrates an error of about 11% for cathode-inside arrangement and 12% in the cathode-outside case for ratios of larger to smaller electrode radius from 1.2 to 10 and a voltage above 0.5 MV up to 5 MV. With these solutions the diode lengths for critical self-magnetic bending and for the condition under which the parapotential model validates are calculated to be longer than 1 cm up to more than 100 cm depending on voltage, radial dimensions and electrode arrangement. The influence of ion flow from the anode on the relativistic electron-only solution is numerically computed, indicating an enhancement factor of total diode current of 1.85 to 4.19 related to voltage, radial dimension and electrode arrangement. 展开更多
关键词 approximate Relativistic solutions for One-Dimensional Cylindrical Coaxial Diode length MV
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AN APPROXIMATE SOLUTION OF NONLINEAR WAVE EQUATION
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作者 袁晓君 王光明 林为干 《Journal of Electronics(China)》 1994年第3期268-272,共5页
A uniformly valid approximate solution of a kind of nonlinear wave equations is studied. The research results indicate that the solution of this kind of equations can be represented by Airy function approximately. The... A uniformly valid approximate solution of a kind of nonlinear wave equations is studied. The research results indicate that the solution of this kind of equations can be represented by Airy function approximately. The usually used W. K. B. approximation is the first order approximation of the present result in the region far away from the turning point of refractivity. At the turning point of refractivity, the present result is still valid. 展开更多
关键词 Nonlinear WAVE EQUATION approximate solution W. K. B. approximATION
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On the approximate solution of synoptic flow equation with discontinuous boundary conditions
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作者 T.M.Popova E.M.Vikhtenko A.G.Zarubin Khabarovsk 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2000年第S1期131-133,共3页
In the present paper we investigate existence and uniqueness generalized solution for initial boundary value problem of synoptic flow equation with discontinuous boundary conditions. We consider Rothe-Galerkin method ... In the present paper we investigate existence and uniqueness generalized solution for initial boundary value problem of synoptic flow equation with discontinuous boundary conditions. We consider Rothe-Galerkin method for given problem and reduce numerical calculations. 展开更多
关键词 the initial BOUNDARY value problem the approximate solution the Rothe-Galerkin method
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Approximate Generalized Conditional Symmetries and Solutions for Nonlinear Filtration Equation with a Small Parameter
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作者 LI Hong LI Jina +1 位作者 WANG Yanyan ZUO Suli 《Wuhan University Journal of Natural Sciences》 CAS CSCD 2015年第6期461-464,共4页
The approximate generalized conditional symmetries of nonlinear filtration equation with a small parameter are studied. The initial-value problem of the equation can be transformed to perturbed Cauchy problem of pertu... The approximate generalized conditional symmetries of nonlinear filtration equation with a small parameter are studied. The initial-value problem of the equation can be transformed to perturbed Cauchy problem of perturbed first-order ordinary dif- ferential equations systems and approximate solutions are obtained by using these symmetries. 展开更多
关键词 nonlinear filtration equation approximate solution initial-value problem
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Truncated series solutions to the(2+1)-dimensional perturbed Boussinesq equation by using the approximate symmetry method
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作者 Xiao-Yu Jiao 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第10期123-129,共7页
In this paper, the(2+1)-dimensional perturbed Boussinesq equation is transformed into a series of two-dimensional(2 D) similarity reduction equations by using the approximate symmetry method. A step-by-step proce... In this paper, the(2+1)-dimensional perturbed Boussinesq equation is transformed into a series of two-dimensional(2 D) similarity reduction equations by using the approximate symmetry method. A step-by-step procedure is used to acquire Jacobi elliptic function solutions to these similarity equations, which generate the truncated series solutions to the original perturbed Boussinesq equation. Aside from some singular area, the series solutions are convergent when the perturbation parameter is diminished. 展开更多
关键词 approximate symmetry method (2+1)-dimensional perturbed Boussinesq equation series solutions convergence of series solutions
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Approximate Formulation and Numerical Solution for Hypersingular Boundary Integral Equations in Plane Elasticity
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作者 马杭 黄兴 《Journal of Shanghai University(English Edition)》 CAS 2003年第2期124-130,共7页
Based on the fact that the singular boundary integrals in the sense of Cauchy principal value can be represented approximately by the mean values of two companion nearly singular boundary integrals, a vary general app... Based on the fact that the singular boundary integrals in the sense of Cauchy principal value can be represented approximately by the mean values of two companion nearly singular boundary integrals, a vary general approach was developed in the paper. In the approach, the approximate formulation before discretization was constructed to cope with the difficulties encountered in the corner treatment in the formulations of hypersingular boundary integral equations. This makes it possible to solve the hypersingular boundary integral equation numerically in a non regularized form and in a local manner by using conforming C 0 quadratic boundary elements and standard Gaussian quadratures similar to those employed in the conventional displacement BIE formulations. The approximate formulation is very convenient to use because the corner information is comprised naturally in the representations of those approximate integrals. Numerical examples in plane elasticity show that with the present approach, the compatible or better results can be achieved in comparison with those of the conventional BIE formulations. 展开更多
关键词 hypersingular boundary integral equation numerical solution approximate formulation splitting distance.
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Local Galerkin Method for the Approximate Solutions to General FPK Equations
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作者 Er Guokang (Civil Engineering Institute, Southwest Jiaotong University Faculty of Science and Technology, University of Macao) 《Advances in Manufacturing》 SCIE CAS 1999年第1期25-29,共5页
In this paper, the method proposed recently by the author for the solution of probability density function (PDF) of nonlinear stochastic systems is presented in detail and extended for more general problems of stochas... In this paper, the method proposed recently by the author for the solution of probability density function (PDF) of nonlinear stochastic systems is presented in detail and extended for more general problems of stochastic differential equations (SDE), therefore the Fokker Planck Kolmogorov (FPK) equation is expressed in general form with no limitation on the degree of nonlinearity of the SDE, the type of δ correlated excitations, the existence of multiplicative excitations, and the dimension of SDE or FPK equation. Examples are given and numerical results are provided for comparing with known exact solution to show the effectiveness of the method. 展开更多
关键词 stochastic differential equations probability density function FPK equation approximate PDF solution local Galerkin method
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WAVELET APPROXIMATE INERTIAL MANIFOLD AND NUMERICAL SOLUTION OF BURGERS' EQUATION
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作者 田立新 许伯强 刘曾荣 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2002年第10期1140-1152,共13页
The existence of approximate inertial manifold Using wavelet to Burgers' equation, and numerical solution under multiresolution analysis with the low modes were studied. It is shown that the Burgers' equation ... The existence of approximate inertial manifold Using wavelet to Burgers' equation, and numerical solution under multiresolution analysis with the low modes were studied. It is shown that the Burgers' equation has a good localization property of the numerical solution distinguishably. 展开更多
关键词 WAVELET wavelet approximate inertial manifold (WAIM) wavelet Galerkin solution infinite dimensional dynamic system
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Approximate analytic solutions for a generalized Hirota—Satsuma coupled KdV equation and a coupled mKdV equation
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作者 赵国忠 蔚喜军 +2 位作者 徐云 朱江 吴迪 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第8期46-54,共9页
This paper applies the variational iteration method to obtain approximate analytic solutions of a generalized Hirota-Satsuma coupled Korteweg-de Vries (KdV) equation and a coupled modified Korteweg-de Vries (mKdV)... This paper applies the variational iteration method to obtain approximate analytic solutions of a generalized Hirota-Satsuma coupled Korteweg-de Vries (KdV) equation and a coupled modified Korteweg-de Vries (mKdV) equation. This method provides a sequence Of functions which converges to the exact solution of the problem and is based on the use of Lagrange multiplier for identification of optimal values of parameters in a functional. Some examples are given to demonstrate the reliability and convenience of the method and comparisons are made with the exact solutions. 展开更多
关键词 approximate analytic solutions generalized Hirota-Satsuma coupled KdV equation coupled mKdV equation variational iteration method
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