Flux-mortar mixed finite element methods with multipoint flux approximation

The flux-mortar mixed finite element method was recently developed in Boon et al. (2022) for a general class of domain decomposition saddle point problems on non-matching grids. In this work we develop the Darcy flow using multipoint flux approximation as subdomain discretization. involve solving positive definite cell-centered pressure systems. normal interfaces is mortar coupling variable, which plays role Lagrange multiplier to impose weakly continuity pressure. We present well-posedness and error analysis based reformulating with quadrature rule. non-overlapping algorithm solution resulting algebraic system that reduces it an interface problem flux-mortar, well efficient preconditioner. A series numerical experiments presented illustrating performance grids, including applications complex porous media.