Stable localized orthogonal decomposition in Raviart-Thomas spaces
Provides a rigorous, pollution-free multiscale method for mixed elliptic problems, benefiting computational homogenization in heterogeneous media.
The paper develops a multiscale method for mixed-formulation elliptic equations using stable localized orthogonal decomposition in Raviart-Thomas spaces, eliminating pollution terms from prior approaches. Numerical experiments confirm its effectiveness.
This work proposes a computational multiscale method for the mixed formulation of a second-order linear elliptic equation subject to a homogeneous Neumann boundary condition, based on a stable localized orthogonal decomposition (LOD) in Raviart-Thomas finite element spaces. In the spirit of numerical homogenization, the construction provides low-dimensional coarse approximation spaces that incorporate fine-scale information from the heterogeneous coefficients by solving local patch problems on a fine mesh. The resulting numerical scheme is accompanied by a rigorous error analysis, and it is applicable beyond periodicity and scale-separation in spatial dimensions two and three. In particular, this novel realization circumvents the presence of pollution terms observed in a previous LOD construction for elliptic problems in mixed formulation. Finally, various numerical experiments are provided that demonstrate the performance of the method.