In reference to continuum mechanics the general macroscopic balance equation of a phase and/or of components that constitute it (accounting also for stoichiometric equations expressing mass transfer due to chemical reactions), involves diffusive and dispersive fluxes of the corresponding extensive quantity (e.g. mass, momentum, heat). Linear expressions of these fluxes called phenomenological (empirical or constitutive) laws suggest on the basis of experimental evidence that these are related to gradients of state variables that correspond to extensive quantities of other interacting phases/components. Phenomena of this kind are referred to as coupled phenomena.

Computational methods for the solution of the coupled (possibly non-linear) set of governing equations are in principle classified into two possible procedures: an iterative scheme for approximate decoupled forms of the original set, or solution of the set as a whole. Both procedures are computational intensive.

Coupled models integrating thermal, hydrological, mechanical and chemical (THMC) data and processes are increasingly important for design and environmental impact assessments of rock and soil related engineering problems such as underground nuclear waste disposal, CO2 geological sequestration, geothermal energy development, landslide and slope stability, and hydropower complexes, etc.

This session is aimed at presenting computational aspects (e.g. efficiency of a numerical algorithm, its consistency, convergent and monotonicity features) for the transport phenomena of multi-fluids and multi-components through possibly deformable porous/fractured media. It is anticipated that presentations will be geared at the latest conceptual and numerical models, computer code developments, and other computational aspects along with practical applications of the THMC models to a wide range of subsurface and engineering problems.