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arXiv 2106.15249math.NAcs.NA
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奇摄动不定常反应-平流-扩散方程正、反问题的收敛性分析

Convergence analysis for forward and inverse problems in singularly perturbed time-dependent reaction-advection-diffusion equations

Dmitrii Chaikovskii, Ye Zhang

摘要:

利用渐近展开法证明了一类含小尺度参数的不定常非线性奇摄动偏微分方程光滑解的存在唯一性.作为一个副产品,我们得到一个近似的光滑的解决方案,构造从一系列减少平稳偏微分方程消失的高阶导数项。我们证明了所构造的近似解的精度在整个区域内可以是这个小尺度参数的任意阶,除了可以忽略的过渡层。此外,基于一个更简单的链接方程之间的近似解和源函数,我们提出了一个有效的算法,称为渐近展开正则化(AER),解决非线性反源问题的原始偏微分方程。证明了AER的收敛速度,并在源函数的一些先验假设下研究了AER的后验误差估计。各种数值例子来证明我们的新方法的效率。

英文摘要:

In this paper, by employing the asymptotic expansion method, we prove the existence and uniqueness of a smoothing solution for a time-dependent nonlinear singularly perturbed partial differential equation (PDE) with a small-scale parameter. As a by-product, we obtain an approximate smooth solution, constructed from a sequence of reduced stationary PDEs with vanished high-order derivative terms. We prove that the accuracy of the constructed approximate solution can be in any order of this small-scale parameter in the whole domain, except a negligible transition layer. Furthermore, based on a simpler link equation between this approximate solution and the source function, we propose an efficient algorithm, called the asymptotic expansion regularization (AER), for solving nonlinear inverse source problems governed by the original PDE. The convergence-rate results of AER are proven, and the a posteriori error estimation of AER is also studied under some a priori assumptions of source functions. Various numerical examples are provided to demonstrate the efficiency of our new approach.

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