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arXiv 2104.02283math.NAcs.NA
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非均匀介质中抛物波近似的计算多尺度方法

Computational multiscale methods for parabolic wave approximations in heterogeneous media

Eric Chung, Yalchin Efendiev, Sai-Mang Pun, Zecheng Zhang

摘要:

本文发展了一种计算多尺度方法来求解具有非均匀和可变介质的抛物波近似。抛物波近似是一种近似全波方程的方法。该方法的一个好处是:一个波的传播方向可以作为一个演化方向,然后我们可以使用经典的格式,如向后欧拉离散它。在此基础上,建立了一套具有不同非均质渗透率场的准气体动力学(QGD)模型。然后,我们采用约束能量最小化广义多尺度有限元法(CEM-GMsFEM)进行空间离散的问题。所得到的系统可以通过结合时间演化的中心差分来求解。由于介质的可变性,我们采用本征正交分解(POD)技术进一步扩展问题的维数,并在POD空间中而不是在所有可能的多尺度基函数所构成的整个多尺度空间中求解相应的模型问题。我们证明了全离散格式的稳定性,并给出了所提出的逼近格式的收敛性分析。数值结果验证了该方法的有效性。

英文摘要:

In this paper, we develop a computational multiscale to solve the parabolic wave approximation with heterogeneous and variable media. Parabolic wave approximation is a technique to approximate the full wave equation. One benefit of the method is that: one wave propagation direction can be taken as an evolution direction, and we then can discretize it using a classical scheme like Backward Euler. Consequently, we obtain a set of quasi-gas-dynamic (QGD) models with different heterogeneous permeability fields. Then, we employ constraint energy minimization generalized multiscale finite element method (CEM-GMsFEM) to perform spatial discretization for the problem. The resulting system can be solved by combining the central difference in time evolution. Due to the variable media, we apply the technique of proper orthogonal decomposition (POD) to further the dimension of the problem and solve the corresponding model problem in the POD space instead of in the whole multiscale space spanned by all possible multiscale basis functions. We prove the stability of the full discretization scheme and give the convergence analysis of the proposed approximation scheme. Numerical results verify the effectiveness of the proposed method.

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