# Operational Modes

Description of the contaminated subsurface environment is founded on governing conservation equations and constitutive functions. Governing coupled flow equations are partial differential equations for the conservation of water mass, air mass, CO_{2} mass, CH_{4} mass, volatile organic compound mass, salt mass, and thermal energy. Constitutive functions relate primary variables to secondary variables. Solution of the governing partial differential equations occurs by the integral volume finite difference method. The governing equations that describe thermal and hydrogeological flow processes are solved simultaneously using Newton-Raphson iteration to resolve the non-linearities in the governing equations. Governing transport equations are partial differential equations for the conservation of solute mass. Solute mass conservation governing equations are solved sequentially, following the solution of the coupled flow equations.

The sequential version of the STOMP simulator currently has 15 operational modes, allowing the user to specify the governing equations that are to be solved. Seven operational modes are available for distribution and the remaining modes are currently restricted as research tools.

Operational Mode | Solved Coupled Equations | Status |
---|---|---|

STOMP-W Water |
water mass | Available |

STOMP-W-R Water with Reactive Transport |
water mass | Available |

STOMP-WAE |
water mass |
Available |

STOMP-WO |
water mass |
Available |

STOMP-WOA |
water mass |
Available |

STOMP-WS Water-Salt |
water mass salt mass |
Available |

STOMP-CO2 |
water mass CO2 mass NaCl mass |
Available |

STOMP-CO2-R |
water mass CO2 mass NaCl mass |
Available |

STOMP-CO2E Water-CO2-Salt-Energy |
water mass CO _{2} massNaCl mass thermal energy |
Available |

STOMP-HYD |
water mass |
Available |

STOMP-WA Water-Air |
water mass air mass |
Research Code |

STOMP-WAE-B |
water mass |
Research Code |

STOMP-WOAE |
water mass |
Research Code |

STOMP-WOD Water-Oil-Dissolved Oil |
water mass oil mass dissolved oil mass |
Research Code |

STOMP-WAS Water-Air-Salt |
water mass air mass salt mass |
Research Code |

STOMP-WASE Water-Air-Salt-Energy |
water mass air mass salt mass thermal energy |
Research Code |

STOMP-OS Oil Shale |
heavy oil mass light oil mass CHX mass CH _{4} massthermal energy |
Research Code |

STOMP-HYD-KE Water-CO2-CH4-Salt-Energy |
water mass mobile CO _{2} massmobile CH _{4} masshydrate CO _{2} masshydrate CH _{4} massthermal energy |
Research Code |

STOMP-HYDT-KE Water-CO2-CH4-N2-Salt-Energy |
water mass mobile CO _{2} massmobile CH _{4} massmobile N _{2} masshydrate CO _{2} masshydrate CH _{4} masshydrate N _{2} massthermal energy |
Research Code |

Note that the operational modes do not comprise all of the possible combinations of coupled governing equations. The combination sets of coupled governing equations selected for inclusion in the list of operational modes represent those with the greatest utility for physical systems. For example, a two-phase non-volatile non-isothermal operational mode could be envisioned, which solved the water mass and energy conservation equations. This operational mode would invoke the assumption of a non-participating gas phase. Two-phase flow and transport through porous media under thermal gradients, however, strongly depends on the diffusion, dispersion, and advection transport through gas phase, even for low thermal gradients. Therefore, this operational mode, while capable of functioning and producing converged solutions, would have limited utility because of its associated premise that gas phase transport could be neglected.