A Continuous Space-Time Mixed Finite Element Method for Sine-Gordon Equations
-
摘要: 该文将混合有限元方法和连续时空有限元方法相结合, 构造了sine-Gordon方程的连续时空混合有限元离散格式, 引入独立变量p=ut来求解, 并将时间变量和空间变量都用有限元方法处理. 此格式可以将方程降阶, 降低有限元空间的光滑性要求, 同时在时间和空间两个方向都能发挥有限元方法的优势, 获得时空高精度的数值解. 理论分析中严格证明了数值解的稳定性, 给出了u和p的误差估计. 最后通过数值算例的结果展示了格式的有效性和可行性.
-
关键词:
- sine-Gordon方程 /
- 连续时空混合有限元 /
- 稳定性 /
- 误差估计
Abstract: The mixed finite element method was combined with the continuous space-time finite element method to construct a continuous space-time mixed finite element scheme for sine-Gordon equations, through the introduction of independent variable p=ut to solve the equations. This scheme uses the finite element method to treat both time and space variables. The space-time mixed finite element scheme can reduce the order of the equation and lower the smoothness requirements on the finite element space. The advantages of the finite element method was utilized in both the time and the space directions, thereby to obtain high-precision space-time numerical solutions. The stability of numerical solutions was strictly proven in the theoretical analysis, and error estimates for u and p were provided. Finally, the effectiveness and feasibility of the proposed method were demonstrated through numerical examples. -
表 1 用线性基函数和k=1/200时, 关于空间方向的误差和收敛阶
Table 1. Error and convergence rates in the space direction with the linear basis function and k=1/200
h ‖p-phk‖a rate log2(k) ‖u-uhk‖a rate log2(k) 1/4 4.739 6E-3 1.781 9E-3 1/8 1.330 1E-3 1.833 3 4.985 6E-4 1.837 6 1/16 3.409 2E-4 1.964 0 1.278 7E-4 1.963 1 1/32 8.578 9E-5 1.990 6 3.217 3E-5 1.990 8 表 2 用线性基函数和k=1/200时, 关于时间方向的误差和收敛阶
Table 2. Error and convergence rates in the time direction with the linear basis function and k=1/200
h ‖p-phk‖a rate log2(k) ‖u-uhk‖a rate log2(k) 1/4 8.072 5E-4 3.590 1E-4 1/8 2.537 4E-4 1.669 7 9.153 6E-5 1.971 6 1/16 6.484 0E-5 1.968 4 2.293 7E-5 1.996 7 1/32 1.664 3E-5 1.962 0 5.793 9E-6 1.985 0 表 3 线性基函数, t=T时刻的误差和收敛阶
Table 3. Error and convergence rates at time t=T for the linear basis function
k(k=10h) 1/4 1/8 1/16 1/32 ‖u-uCN‖b 4.035 9E-3 1.128 9E-3 2.892 0E-4 7.272 5E-5 rate log2(k) 1.837 9 1.964 8 1.991 5 ‖u-uST‖b 1.782 0E-3 4.985 7E-4 1.278 7E-4 3.217 2E-5 rate log2(k) 1.837 6 1.963 1 1.990 8 ‖p-pCN‖b 8.669 2E-3 2.375 9E-3 6.010 2E-4 1.505 1E-4 rate log2(k) 1.867 4 1.982 9 1.997 5 ‖p-pST‖b 8.497 0E-3 2.365 9E-3 6.001 4E-4 1.504 6E-4 rate log2(k) 1.826 4 1.968 9 1.995 7 表 4 二次基函数, t=T时刻的误差和收敛阶
Table 4. Error and convergence rates at time t=T for the quadratic basis function
k(k=10h) 1/2 1/4 1/8 1/16 ‖u-uCN‖b 3.068 6E-3 6.695 7E-4 1.617 0E-4 4.003 1E-5 rate log2(k) 2.196 3 2.049 9 2.014 2 ‖u-uST‖b 7.529 1E-6 7.082 6E-7 8.170 7E-8 9.852 2E-9 rate log2(k) 3.410 1 3.115 7 3.052 0 ‖p-pCN‖b 3.538 7E-3 5.569 8E-4 1.221 2E-4 1.880 6E-5 rate log2(k) 2.667 5 2.189 3 2.699 0 ‖p-pST‖b 7.511 3E-5 8.248 3E-6 7.801 6E-7 7.875 8E-8 rate log2(k) 3.186 9 3.402 3 3.308 2 -
[1] JIWARI R, PANDIT S, MITTAL R C. Numerical simulation of two-dimensional sine-Gordon solitons by differential quadrature method[J]. Computer Physics Communications, 2012, 183(3): 600-616. doi: 10.1016/j.cpc.2011.12.004 [2] XIA Hong, TENG Fei, LUO Zhendong. A reduced-order extrapolating finite difference iterative scheme for 2D generalized nonlinear sine-Gordon equation[J]. Applied and Computational Mathematics, 2018, 7(1): 19-25. doi: 10.11648/j.acm.20180701.13 [3] GUO Benyu, PASCUAL P J, RODRIGUEZ J, et al. Numerical solution of the sine-Gordon equation[J]. Applied Mathematics and Computation, 1986, 18(1): 1-14. doi: 10.1016/0096-3003(86)90025-1 [4] ARGYRIS J, HAASE M, HEINRICH J C. Finite element approximation to two-dimensional sine-Gordon solitons[J]. Computer Methods in Applied Mechanics and Engineering, 1991, 86(1): 1-26. doi: 10.1016/0045-7825(91)90136-T [5] LIU Yang, LI Hong. Numerical solutions of H1-Galerkin mixed finite element method for a damped sine-Gordon equation[J]. Applied Mathematics, 2009, 22(3): 579-588. [6] 常晓慧, 李宏, 何斯日古楞. Sobolev方程的H1-Galerkin时空混合有限元分裂格式[J]. 高校应用数学学报: A辑, 2020, 35(4): 470-486. https://www.cnki.com.cn/Article/CJFDTOTAL-GXYZ202004010.htmCHANG Xiaohui, LI Hong, HE Siriguleng. H1-Galerkin space time mixed finite element splitting scheme for one-dimensional Sobolev equation[J]. Applied Mathematics: A Journal of Chinese Universities, 2020, 35(4): 470-486. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-GXYZ202004010.htm [7] 李宏, 黄春霞, 何斯日古楞, 等. Sine-Gordon方程的三次配点法[J]. 工程数学学报, 2014, 31(2): 254-266. doi: 10.3969/j.issn.1005-3085.2014.02.011LI Hong, HUANG Chunxia, HE Siriguleng, et al. A qualocation method for sine-Gordon equation[J]. Chinese Journal of Engineering Mathematics, 2014, 31(2): 254-266. (in Chinese) doi: 10.3969/j.issn.1005-3085.2014.02.011 [8] 许秋滨, 张鲁明. 二维广义非线性sine-Gordon方程的一个ADI格式[J]. 应用数学学报, 2007, 30(5): 836-846. doi: 10.3321/j.issn:0254-3079.2007.05.009XU Qiubin, ZHANG Luming. An ADI scheme for the generalized nonlinear sine-Gordon equation in two dimensions[J]. Acta Mathematicae Applicatae Sinica, 2007, 30(5): 836-846. (in Chinese) doi: 10.3321/j.issn:0254-3079.2007.05.009 [9] LAI Huilin, MA Changfeng. An implicit scheme of lattice Boltzmann method for sine-Gordon equation[J]. Chinese Physics Letters, 2008, 25(6): 2118-2120. doi: 10.1088/0256-307X/25/6/053 [10] MA Limin, WU Zongmin. A numerical method for one-dimensional nonlinear sine-Gordon equation using multiquadric quasi-interpolation[J]. Chinese Physics B, 2009, 18(8): 3099-3013. doi: 10.1088/1674-1056/18/8/001 [11] HASHEMI M S. Numerical study of the one-dimensional coupled nonlinear sine-Gordon equations by a novel geometric meshless method[J]. Engineering With Computers, 2021, 37(4): 3397-3407. doi: 10.1007/s00366-020-01001-2 [12] 石东洋, 张斐然. Sine-Gordon方程的一类低阶非协调有限元分析[J]. 计算数学, 2011, 33(3): 289-297. https://www.cnki.com.cn/Article/CJFDTOTAL-JSSX201103008.htmSHI Dongyang, ZHANG Feiran. A class of low order nonconforming finite element analysis for Sine-Gordon equation[J]. Mathematica Numerica Sinica, 2011, 33(3): 289-297. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-JSSX201103008.htm [13] ADAMS R A. Sobolev Spaces[M]. New York: Academic Press, 1975. [14] 罗振东. 混合有限元法基础及其应用[M]. 北京: 科学出版社, 2006.LUO Zhendong. Fundamentals and Applications of Mixed Finite Element Method[M]. Beijing: Science Press, 2006. (in Chinese) [15] AZIZ A K, MONK P. Continuous finite elements in space and time for the heat equation[J]. Mathematics of Computation, 1989, 52(186): 255-274. doi: 10.1090/S0025-5718-1989-0983310-2 [16] LUO Zhendong, CHEN Goong. Proper Orthogonal Decomposition Methods for Partial Differential Equations[M]. San Diego: Academic Press of Elsevier, 2018. -