scholarly journals An adaptive finite element DtN method for the elastic wave scattering by biperiodic structures

Author(s):  
Gang Bao ◽  
Xue Jiang ◽  
Peijun Li ◽  
Xiaokai Yuan

Consider the scattering of a time-harmonic elastic plane wave by a bi-periodic rigid surface. The displacement of elastic wave motion is modeled by the three-dimensional Navier equation in an unbounded domain above the surface. Based on the Dirichlet-to-Neumann (DtN) operator, which is given as an infinite series, an exact transparent boundary condition is introduced and the scattering problem is formulated equivalently into a boundary value problem in a bounded domain. An a posteriori error estimate based adaptive finite element DtN method is proposed to solve the discrete variational problem where the DtN operator is truncated into a finite number of terms. The a posteriori error estimate takes account of the finite element approximation error and the truncation error of the DtN operator which is shown to decay exponentially with respect to the truncation parameter. Numerical experiments are presented to illustrate the effectiveness of the proposed method.

2019 ◽  
Vol 16 (04) ◽  
pp. 1850096
Author(s):  
Zhoufeng Wang ◽  
Lingxue Zhu

This paper is concerned with the diffraction by a polygonal-line grating. We develop a continuous interior penalty finite element method based on the truncation of the nonlocal boundary operators for solving the problem. An a posteriori error estimate is derived for the method. The truncation parameter is determined through the truncation error of the a posteriori error estimate. Numerical experiments are also presented to show the efficiency and robustness of the proposed adaptive algorithm.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Houédanou Koffi Wilfrid

In this work, we develop an a posteriori error analysis of a conforming mixed finite element method for solving the coupled problem arising in the interaction between a free fluid and a fluid in a poroelastic medium on isotropic meshes in ℝ d , d ∈ 2 , 3 . The approach utilizes a Lagrange multiplier method to impose weakly the interface conditions [Ilona Ambartsumyan et al., Numerische Mathematik, 140 (2): 513-553, 2018]. The a posteriori error estimate is based on a suitable evaluation on the residual of the finite element solution. It is proven that the a posteriori error estimate provided in this paper is both reliable and efficient. The proof of reliability makes use of suitable auxiliary problems, diverse continuous inf-sup conditions satisfied by the bilinear forms involved, Helmholtz decomposition, and local approximation properties of the Clément interpolant. On the other hand, inverse inequalities and the localization technique based on simplexe-bubble and face-bubble functions are the main tools for proving the efficiency of the estimator. Up to minor modifications, our analysis can be extended to other finite element subspaces yielding a stable Galerkin scheme.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Houédanou Koffi Wilfrid ◽  
Adetola Jamal ◽  
Allaoui Mohamed

In this paper, we develop an a posteriori error analysis for the stationary Stokes-Darcy coupled problem approximated by conforming the finite element method on isotropic meshes in ℝ d , d ∈ 2 , 3 . The approach utilizes a new robust stabilized fully mixed discretization. The a posteriori error estimate is based on a suitable evaluation on the residual of the finite element solution plus the stabilization terms. It is proven that the a posteriori error estimate provided in this paper is both reliable and efficient.


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