History

TOUGH+ is the successor of the TOUGH2 suite of nonisothermal multiphase flow simulators originally developed in the early 1980s by Karsten Pruess of Lawrence Berkeley National Laboratory. The code was continually enhanced by LBNL researchers and collaborators through the addition of new fluid property modules, refined process descriptions, and added user features. The history of TOUGH2 has been described in Pruess ["The TOUGH Codes—A Family of Simulation Tools for Multiphase Flow and Transport Processes in permeable Media," Vadose Zone Journal, 3, 738–746, 2004]. The suite of codes includes the following major simulators:

  • TOUGH2, a general-purpose simulator that consists of modules describing a variety of components and phase combinations
  • T2VOC and TMVOC, which focus on environmental contamination problems with non-aqueous phase liquids
  • TOUGHREACT, which couples TOUGH2 with a general chemical speciation and reaction package
  • TOUGH-FLAC, which couples TOUGH2 with the commercial rock mechanics code FLAC3D
  • iTOUGH2, which provides inverse modeling capabilities for many of the TOUGH2 modules.

In addition to these major codes, many specialized modules have been developed for specific applications, including modules that handle non-Newtonian fluids, biogeochemical reactions, and explosive components. Other modules deal with processes specific to acid mine drainage problems or landfills; they may handle non-Darcy flow conditions, are coupled to surface flow and the atmosphere, or are linked to geophysical codes or system level models. Different linear equation solver packages are available, as well as vectorized and parallelized versions of the code.

TOUGH+ is the result of a re-engineering effort (headed by George Moridis) in which the capabilities of TOUGH2 have been recast in a modular design that adheres to the tenets of object-oriented programming as implemented in Fortran 95. New capabilities have been added (e.g., the range of thermodynamic properties of water has been extended to include ice). The first module released in the new framework is TOUGH+Hydrate for the simulation of processes in hydrate-bearing formations. Additional TOUGH+ modules are currently being developed; they will be released as they become available. TOUGH+ maintains backwards compatibility with TOUGH2 input files.