求解二维Fisher-KPP方程的一类保正保界差分格式及其Richardson外推法  

A POSITIVITY AND BOUNDEDNESS PRESERVING DIFFERENCE SCHEME AND ITS RICHARDSON EXTRAPOLATION METHOD FOR SOLVING A TWO-DIMENSIONAL FISHER-KPP EQUATION

作　　者：邓定文[1] 赵紫琳 Deng Dingwen;Zhao Zilin(School of Mathematics and Information Science,Nanchang Hangkong University,Nanchang 330063,China)

机构地区：[1]南昌航空大学数学与信息科学学院,南昌330063

出　　处：《计算数学》2022年第4期561-584,共24页Mathematica Numerica Sinica

基　　金：国家自然科学基金(11861047,11871393);江西省自然科学基金(20202BABL201005);陕西省国际合作计划重点项目(2019KWZ-08);江西省杰出青年基金(20212ACB211006).

摘　　要：本文研究求解二维Fisher-Kolmogorov-Petrovsky-Piscounov(Fisher-KPP)方程的一类保正保界差分格式,运用能量分析法证明了当网格比满足R_(x)+R_(y)+[bτ(p-1)]/2≤1/2时差分解具有一系列数学性质,包括保正性、保界性和单调性,且在无穷范数意义下有O(τ+h_(x)^(2)+h_(y)^(2))的收敛阶.然后通过发展Richardson外推法得到收敛阶为O(τ+h_(x)^(4)+h_(y)^(4))的外推解.最后数值实验表明数值结果与理论结果相吻合.值得提及的是在运用本文构造的Richardson外推法时对时空网格比没有增加更严格的条件。In this paper,a positivity-preserving difference scheme is studied for two-dimensional Fisher-Kolmogorov-Petrovsky-Piscounov equation(Fisher-KPP).The energy analysis method is used to prove that the difference scheme has a series of mathematical properties,including preserving positivity,preserving boundedness,preserving monotonicity,and has a convergence order of O(τ+h_(x)^(2)+h_(y)^(2))in maximum norm,when the ratio of temporal meshsize to spatial meshsizes satisfy Ra,+Ry+[br(p-1)]/2≤.Then by developing Richardson extrapolation methods(REMs),the extrapolation solutions with convergence orders of O(τ+h_(x)^(4)+h_(y)^(4))are obtained.Finally,two numerical examples are given to confirm that the numerical results agree well with the theoretical results.It is worthwhile meaning that the condition of the ratios of temporal meshsize to spatial meshsizes as the current REMs are used are the same as the one of the original numerical method.

关 键 词：二维Fisher-Kolmogorov-Petrovsky-Piscounov(Fisher-KPP)方程 保正保界的差分格式 收敛性 Richardson外推法. 

分 类 号：O241.82[理学—计算数学]