共查询到20条相似文献,搜索用时 34 毫秒
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Gordon L. Olson 《Journal of computational physics》2011,230(20):7548-7566
An existing solution method for solving the multigroup radiation equations, linear multifrequency-grey acceleration, is here extended to be second order in time. This method works for simple diffusion and for flux-limited diffusion, with or without material conduction. A new method is developed that does not require the solution of an averaged grey transport equation. It is effective solving both the diffusion and P1 forms of the transport equation. Two dimensional, multi-material test problems are used to compare the solution methods. 相似文献
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Homogeneous balance method for solving nonlinear partial differential equation(s) is extended to solving initial-value problem and getting new solution(s) from a known solution of the equation(s) under consideration. The approximate equations for long water waves are chosen to illustrate the method, infinitely many simple-solitary-wave solutions and infinitely many rational function solutions, especially the closed form of the solution for initial-value problem, are obtained by using the extended homogeneous balance method given here. 相似文献
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Sinc-collocation method is applied for solving Blasius equation which comes from boundary layer equations. It is well known that sinc procedure converges to the solution at an exponential rate. Comparison with Howarth and Asaithambi's numerical solutions reveals that the proposed method is of high accuracy and reduces the solution of Blasius' equation to the solution of a system of algebraic equations. 相似文献
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Jianhong Yang Lei Gang & Jianwei Yang 《advances in applied mathematics and mechanics.》2014,6(5):663-679
In this paper, we consider a two-scale stabilized finite volume method for the two-dimensional
stationary incompressible flow approximated by the lowest equal-order element pair $P_1-P_1$
which does not satisfy the inf-sup condition. The two-scale method consists of solving a small non-linear system
on the coarse mesh and then solving a linear Stokes equations on the fine mesh. Convergence of the optimal
order in the $H^1$-norm for velocity and the $L^2$-norm for pressure is obtained. The error analysis shows
there is the same convergence rate between the two-scale stabilized finite volume solution and the usual
stabilized finite volume solution on a fine mesh with relation $h =\mathcal{O}(H^2)$. Numerical experiments completely
confirm theoretic results. Therefore, this method presented in this paper is of practical importance in
scientific computation. 相似文献
6.
We present a new technique for solving the radiative transfer equation in a differentially moving atmosphere. The method is based on a pertubation of the solution of the transfer problem in a static atmosphere. The perturbation technique may be applied with any method for solving the static atmosphere problem and leads to significant reductions in computer time and storage requirements.The method is flexible and may be used to solve problems involving depth dependence in any of the parameters of the transfer equation. 相似文献
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A reduces equation of the Kelvin wave is considered. By
using the homotopic mapping solving method, the approximate solution
is obtained. The homptopic mapping method is an analytic method,
the obtained solution can analyse operations sequentially. 相似文献
9.
使用中子密度一阶泰劳多项式分段近似技术,给出一个新的求解点堆中子动力学方程组的数值方法并采用全隐格式以克服方程组的刚性,同时确保解的必要精度。数值结果表明:在隐式一阶多项式近似下,对合适的反应性输入能够取得足够精确的结果。当反应性给定时,对于求解反应堆动力学问题,能给出一个简法的计算过程。 相似文献
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Few-Projection Tomography. I. Radio-Astronomical Approach for the Problem and the 2-CLEAN DSA Method
M. I. Agafonov 《Radiophysics and Quantum Electronics》2004,47(2):85-99
We develop the radio-astronomical approach for solving the few-projection tomography problem. It is shown that the 2-CLEAN DSA method proposed for determination of the permissible solution area is an efficient way for solving this problem. The method is based on solving the deconvolution problem with allowance for the synthesized beam or the synthesized Green's function. The distortions due to the sidelobe responses of the synthesized transfer function are eliminated by using two realizations of the well-known iterative radio-astronomical CLEAN algorithm with nonlinear constraints. The proposed 2-CLEAN DSA method allows one to decrease the number of projections required for two-dimensional reconstruction by a factor of about 10 as compared with the conventional tomography approach, provided that a wide spatial-frequency spectrum limited from above is reconstructed. The method can easily be adapted to introducing additional constraints. Examples of astrotomography reconstruction are presented. We show that the proposed method is promising for a large number of remote sensing applications and compare it with other well-known reconstruction techniques. The papers by radio astronomers, who contributed significantly to the development of components of the method, are pointed out. 相似文献
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Edward Harms 《Nuclear Physics A》1975,247(1):51-58
The improved method of moments procedure which was developed in an earlier paper is applied to the solution of the three-body scattering equations for separable two-body interactions. Results of these calculations further support conclusions reached previously that the improved method of moments provides a rapid and accurate calculational procedure for solving scattering problems. 相似文献
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Burin Gumjudpai 《General Relativity and Gravitation》2009,41(2):249-265
We report a method of solving for canonical scalar field exact solution in a non-flat FLRW universe with barotropic fluid using non-linear Schrödinger (NLS)-type formulation in comparison to the method in the standard Friedmann framework. We consider phantom and non-phantom scalar field cases with exponential and power-law accelerating expansion. Analysis on effective equation of state to both cases of expansion is also performed. We speculate and comment on some advantage and disadvantage of using the NLS formulation in solving for the exact solution. 相似文献
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JiaQi Mo 《中国科学G辑(英文版)》2009,52(7):1007-1010
The model for gain fluency of a laser pulse amplifier is studied. Using the homotopic mapping method, firstly, the system
of the original model is packed up standardization; secondly, introducing a homotopic mapping, taking the property of the
mapping, inducing a contrived parameter, the solving of a nonlinear problem translates into the solving of a linear problem.
Then the approximate expressions of the solution for the corresponding model are obtained. And the precision for the approximate
solution is compared. It illuminates that the obtained approximate solution using the homotopic mapping method possesses higher
approximate degree. At one time, the expansion of solution through the homotopic mapping method can be kept in the analytic
operation. Thus it also enables us through differential and integral operations to obtain other physics behavior for the gain
fluency of laser pulse amplifier. 相似文献
14.
The Poisson’s equation in a two-dimensional domain that contains star metal-dielectric corners is considered. The corners can be only metal or only dielectric. In their neighborhood, the solution is bounded, but the gradient has power-law singularities. A numerical algorithm for solving this problem is proposed. The algorithm is based on the finite-element method and takes the asymptotic behavior of the solution in the neighborhood of metal-dielectric corners into account. 相似文献
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In this Letter we propose a pseudospectral method for solving Thomas-Fermi equation which is a nonlinear ordinary differential equation on semi-infinite interval. This approach is based on rational Chebyshev pseudospectral method. This method reduces the solution of this problem to the solution of a system of algebraic equations. Comparison with some numerical solutions shows that the present solution is highly accurate. 相似文献
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Alexander Kyurkchan Elena A. Skorodoumova 《Journal of Quantitative Spectroscopy & Radiative Transfer》2006,100(1-3):207-219
The pattern equations method is extended to solving the diffraction problem on a group of bodies. The problem is reduced to solving an algebraic system of equations with respect to the expansion coefficients of the scattering patterns by using a series expansion of the scattering patterns in angular spherical harmonics. The explicit (asymptotic) solution of the problem is obtained in a case when the scattering bodies are far enough from each other. 相似文献
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A new method is proposed for solving the integral equation for the overall adsorption isotherm, with respect to the energy distribution function. This method can be applied for arbitrary integration limits; finite or infinite. The purpose of the calculations carried out was to examine the solution of the integral equation in relation to accepted integration limits. 相似文献
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D. E. Silin 《Radiophysics and Quantum Electronics》2011,53(11):666-678
We present a rigorous method for solving the problems of diffraction of monochromatic electromagnetic waves on periodic structures
of many types. The method is based on transformation of the Helmholtz equation and the boundary conditions to a certain system
of integral equations and a subsequent rigorous solution of this system. 相似文献
19.
T. Paszkiewicz 《Physica A》1984,123(1):161-174
The Lorentz model of a rarefied gas is used for testing two different methods of solving the Boltzman kinetic equation. It is shown that the Zwanzig-Mori method gives the generalized diffusion equation which agrees with the exact Hauge solution. The Zubarev-Khonkin approach gives a series expansion of the exact generalized diffusion coefficient. Their method is compared with the Chapman-Enskog method. 相似文献
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Through analysing the exact solution of some nonlinear
models, the role of the variable separating method in solving
nonlinear equations is discussed. We find that rich solution
structures of some special fields of these equations come from the
nonzero seed solution. However, these nonzero seed solutions is
likely to result in the divergent phenomena for the other field
component of the same equation. The convergence and the
signification of all field components should be discussed when
someone solves the nonlinear equation using the variable separating
method. 相似文献