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In this paper, a finite volume element (FVE) method is considered for spatial approximations of time fractional diffusion equations involving a Riemann-Liouville fractional derivative of order in time. Improving upon earlier results [Karaa et al., IMA J. Numer. Anal. 37 (2017) 945–964], error estimates in - and -norms for the semidiscrete problem with smooth and mildly smooth initial data, i.e., and are established. For nonsmooth data, that is, , the optimal -error estimate is shown to hold only under an additional assumption on the triangulation, which is known to be satisfied for symmetric triangulations. Superconvergence result is also proved and as a consequence, a quasi-optimal error estimate is established in the -norm. Further, two fully discrete schemes using convolution quadrature in time generated by the backward Euler and the second-order backward difference methods are analyzed, and error estimates are derived for both smooth and nonsmooth initial data. Based on a comparison of the standard Galerkin finite element solution with the FVE solution and exploiting tools for Laplace transforms with semigroup type properties of the FVE solution operator, our analysis is then extended in a unified manner to several time fractional order evolution problems. Finally, several numerical experiments are conducted to confirm our theoretical findings.
Karaa, Samir 1 ; Pani, Amiya K. 1
@article{M2AN_2018__52_2_773_0, author = {Karaa, Samir and Pani, Amiya K.}, title = {Error analysis of a {FVEM} for fractional order evolution equations with nonsmooth initial data}, journal = {ESAIM: Mathematical Modelling and Numerical Analysis }, pages = {773--801}, publisher = {EDP-Sciences}, volume = {52}, number = {2}, year = {2018}, doi = {10.1051/m2an/2018029}, mrnumber = {3834443}, zbl = {1404.65114}, language = {en}, url = {http://geodesic.mathdoc.fr/articles/10.1051/m2an/2018029/} }
TY - JOUR AU - Karaa, Samir AU - Pani, Amiya K. TI - Error analysis of a FVEM for fractional order evolution equations with nonsmooth initial data JO - ESAIM: Mathematical Modelling and Numerical Analysis PY - 2018 SP - 773 EP - 801 VL - 52 IS - 2 PB - EDP-Sciences UR - http://geodesic.mathdoc.fr/articles/10.1051/m2an/2018029/ DO - 10.1051/m2an/2018029 LA - en ID - M2AN_2018__52_2_773_0 ER -
%0 Journal Article %A Karaa, Samir %A Pani, Amiya K. %T Error analysis of a FVEM for fractional order evolution equations with nonsmooth initial data %J ESAIM: Mathematical Modelling and Numerical Analysis %D 2018 %P 773-801 %V 52 %N 2 %I EDP-Sciences %U http://geodesic.mathdoc.fr/articles/10.1051/m2an/2018029/ %R 10.1051/m2an/2018029 %G en %F M2AN_2018__52_2_773_0
Karaa, Samir; Pani, Amiya K. Error analysis of a FVEM for fractional order evolution equations with nonsmooth initial data. ESAIM: Mathematical Modelling and Numerical Analysis , Tome 52 (2018) no. 2, pp. 773-801. doi: 10.1051/m2an/2018029
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