TY - JOUR

T1 - A Highly-Accurate Finite Element Method with Exponentially Compressed Meshes for the Solution of the Dirichlet Problem of the generalized Helmholtz Equation with Corner Singularities

AU - Celiker, Emine

AU - Lin, Ping

N1 - E. Celiker's work is supported by the EU Scholarship Programme for the Turkish Cypriot Community 2017/18.

PY - 2019/12/1

Y1 - 2019/12/1

N2 - In this study, a highly-accurate, conforming finite element method is developed and justified for the solution of the Dirichlet problem of the generalized Helmholtz equation on domains with re-entrant corners. The k−th order Lagrange elements are used for the discretization of the variational form of the problem on exponentially compressed polar meshes employed in the neighbourhood of the corners whose interior angle is απ, α≠1∕2, and on the triangular and curved mesh formed in the remainder of the polygon. The exponentially compressed polar meshes are constructed such that they are transformed to square meshes using the Log-Polar transformation, simplifying the realization of the method significantly. For the error bound between the exact and the approximate solution obtained by the proposed method, an accuracy of O(h
k),h mesh size and k≥1 an integer, is obtained in the H
1-norm. Numerical experiments are conducted to support the theoretical analysis made. The proposed method can be applied for dealing with the corner singularities of general nonlinear parabolic partial differential equations with semi-implicit time discretization.

AB - In this study, a highly-accurate, conforming finite element method is developed and justified for the solution of the Dirichlet problem of the generalized Helmholtz equation on domains with re-entrant corners. The k−th order Lagrange elements are used for the discretization of the variational form of the problem on exponentially compressed polar meshes employed in the neighbourhood of the corners whose interior angle is απ, α≠1∕2, and on the triangular and curved mesh formed in the remainder of the polygon. The exponentially compressed polar meshes are constructed such that they are transformed to square meshes using the Log-Polar transformation, simplifying the realization of the method significantly. For the error bound between the exact and the approximate solution obtained by the proposed method, an accuracy of O(h
k),h mesh size and k≥1 an integer, is obtained in the H
1-norm. Numerical experiments are conducted to support the theoretical analysis made. The proposed method can be applied for dealing with the corner singularities of general nonlinear parabolic partial differential equations with semi-implicit time discretization.

KW - Error analysis

KW - Finite element method

KW - Helmholtz equation

KW - Mesh refinement

KW - Singularity problem

UR - http://www.scopus.com/inward/record.url?scp=85065207607&partnerID=8YFLogxK

U2 - 10.1016/j.cam.2019.04.004

DO - 10.1016/j.cam.2019.04.004

M3 - Article

VL - 361

SP - 227

EP - 235

JO - Journal of Computational and Applied Mathematics

JF - Journal of Computational and Applied Mathematics

SN - 0377-0427

ER -