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Sobolev方程的H^1-Galerkin时空混合有限元分裂格式 被引量:2
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作者 常晓慧 李宏 何斯日古楞 《高校应用数学学报(A辑)》 北大核心 2020年第4期470-486,共17页
研究了一维Sobolev方程的H^1-Galerkin时空混合有限元分裂格式,格式中有限元空间可以利用不同次数的多项式空间,不需要满足LBB条件,避免求解耦合方程组,能同时得到时间和空间两个变量的形式高阶精度,且能同时高精度逼近渗透流体的浓度u... 研究了一维Sobolev方程的H^1-Galerkin时空混合有限元分裂格式,格式中有限元空间可以利用不同次数的多项式空间,不需要满足LBB条件,避免求解耦合方程组,能同时得到时间和空间两个变量的形式高阶精度,且能同时高精度逼近渗透流体的浓度u,浓度梯度q和流体通量σ.通过格式分裂,时空统一处理,引入时空投影算子等方法,证明了H^1-Galerkin时空混合有限元解的存在唯一性,稳定性和误差估计,并给出数值算例验证格式的有效性和可行性以及理论分析结果的合理性. 展开更多
关键词 SOBOLEV方程 H^1-Galerkin时空混合有限元方法 分裂格式 存在唯一性和稳定性 误差估计 数值算例
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A Study on the Nonlinear Caputo-Type Snakebite Envenoming Model with Memory
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作者 Pushpendra Kumar Vedat Suat Erturk +1 位作者 V.Govindaraj Dumitru Baleanu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第9期2487-2506,共20页
In this article,we introduce a nonlinear Caputo-type snakebite envenoming model with memory.The well-known Caputo fractional derivative is used to generalize the previously presented integer-order model into a fractio... In this article,we introduce a nonlinear Caputo-type snakebite envenoming model with memory.The well-known Caputo fractional derivative is used to generalize the previously presented integer-order model into a fractionalorder sense.The numerical solution of the model is derived from a novel implementation of a finite-difference predictor-corrector(L1-PC)scheme with error estimation and stability analysis.The proof of the existence and positivity of the solution is given by using the fixed point theory.From the necessary simulations,we justify that the first-time implementation of the proposedmethod on an epidemicmodel shows that the scheme is fully suitable and time-efficient for solving epidemic models.This work aims to show the novel application of the given scheme as well as to check how the proposed snakebite envenoming model behaves in the presence of the Caputo fractional derivative,including memory effects. 展开更多
关键词 Mathematical model Caputo fractional derivative L1-predictor-corrector method error estimation stability graphical simulations
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粘弹性波动方程的H^(1)-Galerkin时空混合有限元分裂格式
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作者 王嘉华 李宏 《计算数学》 CSCD 北大核心 2023年第2期177-196,共20页
构造一维粘弹性波动方程的H^(1)-Galerkin时空有限元分裂格式.这种新的分裂格式在时空两个方向同时利用有限元离散,具有H^(1)-Galerkin混合有限元方法和时空有限元方法的优点,如在不受LBB相容性条件限制的同时能够高精度逼近流体的压力... 构造一维粘弹性波动方程的H^(1)-Galerkin时空有限元分裂格式.这种新的分裂格式在时空两个方向同时利用有限元离散,具有H^(1)-Galerkin混合有限元方法和时空有限元方法的优点,如在不受LBB相容性条件限制的同时能够高精度逼近流体的压力和达西速度,有限元空间可以利用不同次数的多项式空间,能同时得到时间和空间两个变量的形式高阶精度等.通过构造时空投影算子并讨论其相关逼近性质,证明了解的存在唯一性和稳定性,给出混合时空有限元解的误差估计,给出数值算例验证了理论推导结果的合理性和算法的有效性,并和传统H^(1)-Galerkin方法做比较,得到了更小的误差和超收敛阶. 展开更多
关键词 粘弹性波动方程 H^(1)-Galerkin时空混合有限元方法 分裂格式 存在唯一性和稳定性 误差估计 数值算例
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四阶抛物偏微分方程的H^1-Galerkin混合元方法及数值模拟 被引量:10
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作者 刘洋 李宏 +2 位作者 何斯日古楞 高巍 方志朝 《计算数学》 CSCD 北大核心 2012年第3期259-274,共16页
到目前为止,H^1-Galerkin混合有限元方法研究的问题仅局限于二阶发展方程.然而对于高阶发展方程,特别是重要的四阶发展方程问题的研究却没有出现.本文首次提出四阶发展方程的H^1-Galerkin混合有限元方法,为了给出理论分析的需要,我们考... 到目前为止,H^1-Galerkin混合有限元方法研究的问题仅局限于二阶发展方程.然而对于高阶发展方程,特别是重要的四阶发展方程问题的研究却没有出现.本文首次提出四阶发展方程的H^1-Galerkin混合有限元方法,为了给出理论分析的需要,我们考虑四阶抛物型发展方程.通过引进三个适当的中间辅助变量,形成四个一阶方程组成的方程组系统,提出四阶抛物型方程的H^1-Galerkin混合有限元方法.得到了一维情形下的半离散和全离散格式的最优收敛阶误差估计和多维情形的半离散格式误差估计,并采用迭代方法证明了全离散格式的稳定性.最后,通过数值例子验证了提出算法的可行性.在一维情况下我们能够同时得到未知纯量函数、一阶导数、负二阶导数和负三阶导数的最优逼近解,这一点是以往混合元方法所不能得到的. 展开更多
关键词 四阶抛物偏微分方程 H^1-Galerkin混合元方法 稳定性 最优阶误差估计
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Nonconforming H^1-Galerkin Mixed FEM for Sobolev Equations on Anisotropic Meshes 被引量:26
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作者 Dong-yang Shi Hai-hong Wang 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2009年第2期335-344,共10页
A nonconforming H^1-Calerkin mixed finite element method is analyzed for Sobolev equations on anisotropic meshes. The error estimates are obtained without using Ritz-Volterra projection.
关键词 Nonconforming H^1-Galerkin mixed finite element method Sobolev equations anisotropic meshes error estimates
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An H^1-Galerkin Nonconforming Mixed Finite Element Method for Integro-Differential Equation of Parabolic Type 被引量:21
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作者 SHI Dong Yang WANG Hai Hong 《Journal of Mathematical Research and Exposition》 CSCD 2009年第5期871-881,共11页
H1-Galerkin nonconforming mixed finite element methods are analyzed for integro-differential equation of parabolic type.By use of the typical characteristic of the elements,we obtain that the Galerkin mixed approximat... H1-Galerkin nonconforming mixed finite element methods are analyzed for integro-differential equation of parabolic type.By use of the typical characteristic of the elements,we obtain that the Galerkin mixed approximations have the same rates of convergence as in the classical mixed method,but without LBB stability condition. 展开更多
关键词 H^1-Galerkin mixed method integro-differential equation of parabolic type non- conforming semi-discrete scheme full discrete scheme error estimates.
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Fully Discrete H^(1) -Galerkin Mixed Finite Element Methods for Parabolic Optimal Control Problems 被引量:1
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作者 Tianliang Hou Chunmei Liu Hongbo Chen 《Numerical Mathematics(Theory,Methods and Applications)》 SCIE CSCD 2019年第1期134-153,共20页
In this paper,we investigate a priori and a posteriori error estimates of fully discrete H^(1)-Galerkin mixed finite element methods for parabolic optimal control prob-lems.The state variables and co-state variables a... In this paper,we investigate a priori and a posteriori error estimates of fully discrete H^(1)-Galerkin mixed finite element methods for parabolic optimal control prob-lems.The state variables and co-state variables are approximated by the lowest order Raviart-Thomas mixed finite element and linear finite element,and the control vari-able is approximated by piecewise constant functions.The time discretization of the state and co-state are based on finite difference methods.First,we derive a priori error estimates for the control variable,the state variables and the adjoint state variables.Second,by use of energy approach,we derive a posteriori error estimates for optimal control problems,assuming that only the underlying mesh is static.A numerical example is presented to verify the theoretical results on a priori error estimates. 展开更多
关键词 Parabolic equations optimal control problems a priori error estimates a posteriori error estimates H^(1)-Galerkin mixed finite element methods
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TWO-GRID ALGORITHM OF H^(1)-GALERKIN MIXED FINITE ELEMENT METHODS FOR SEMILINEAR PARABOLIC INTEGRO-DIFFERENTIAL EQUATIONS
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作者 Tianliang Hou Chunmei Liu +2 位作者 Chunlei Dai Luoping Chen Yin Yang 《Journal of Computational Mathematics》 SCIE CSCD 2022年第5期667-685,共19页
In this paper,we present a two-grid discretization scheme for semilinear parabolic integro-differential equations by H1-Galerkin mixed finite element methods.We use the lowest order Raviart-Thomas mixed finite element... In this paper,we present a two-grid discretization scheme for semilinear parabolic integro-differential equations by H1-Galerkin mixed finite element methods.We use the lowest order Raviart-Thomas mixed finite elements and continuous linear finite element for spatial discretization,and backward Euler scheme for temporal discretization.Firstly,a priori error estimates and some superclose properties are derived.Secondly,a two-grid scheme is presented and its convergence is discussed.In the proposed two-grid scheme,the solution of the nonlinear system on a fine grid is reduced to the solution of the nonlinear system on a much coarser grid and the solution of two symmetric and positive definite linear algebraic equations on the fine grid and the resulting solution still maintains optimal accuracy.Finally,a numerical experiment is implemented to verify theoretical results of the proposed scheme.The theoretical and numerical results show that the two-grid method achieves the same convergence property as the one-grid method with the choice h=H^(2). 展开更多
关键词 Semilinear parabolic integro-differential equations H^(1)-Galerkin mixed finite element method A priori error estimates Two-grid Superclose.
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任意四边形网格上扩散问题的一个稳定九点格式
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作者 洪旗 苏帅 《数值计算与计算机应用》 2019年第1期51-67,共17页
通过修正Q_1有限体积元方法处理节点未知量,本文提出且分析了扩散问题的一个稳定的九点格式.基于修正Q_1有限体积元格式理论和离散泛函分析,我们在弱几何条件给出了稳定性分析和H^1误差估计.与已有的一些中心型和杂交型格式相比,该格式... 通过修正Q_1有限体积元方法处理节点未知量,本文提出且分析了扩散问题的一个稳定的九点格式.基于修正Q_1有限体积元格式理论和离散泛函分析,我们在弱几何条件给出了稳定性分析和H^1误差估计.与已有的一些中心型和杂交型格式相比,该格式不遭受所谓的数值热障现象.但是该格式需要多求解一次线性方程组.数值实验表明了格式有效性并且验证了理论分析. 展开更多
关键词 扩散问题 九点格式 修正Q1有限体积元 稳定性和H^1误差估计
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