Separating fluid and solid contact constraints for hydro-mechanically coupled finite elements discretising fluid displacement

Abstract

In the simulation of multi-phase porous media in contact with a structure, the contact constraints to be enforced depend on the spatially discretised variables and additional physical considerations. Typically, fluids in porous media behave differently at the contact interface than the solid phase through which they flow. Aspects of numerical modelling and considerations in defining constraints to model such phenomena are discussed in this work. To this end, a hydro-mechanically coupled finite element formulation discretising fluid displacement is supplemented by a mortar contact discretisation scheme enforcing the contact constraints separately for the different phases. Using the proposed multi-phase mortar contact formulation, it is demonstrated for which type of problems such a formulation offers advantages over formulations not distinguishing contact constraints of multiple phases.