# Quick guide to writing a PFLOTRAN input file

## Units

Unless otherwise specified, the units in the input deck are assumed to be:

• Pressure: Pascal [Pa] (absolute)
• Temperature: Celcius [C]
• Distance: meter [m]
• Volume: meter3 [m3]
• Time: second [s]
• Velocity: meters/second [m/s]
• Concentration: molarity [M] or molality [m] if MOLAL keyword used in CHEMISTRY card
• Enthalpy: kilojoules/mole [KJ/mol]
• Mass: kilograms [kg]
• Rate: mass/time [kg/s] or volume/time [m3/s]
• Rock density: kilograms/meter3 [kg/m3]

## Example Input Decks

Simple Flow Problem: Simple, vertical 1D variably-saturated flow.

## Input Deck Specification

PFLOTRAN input files are divided into blocks based on the process models employed. Process models are defined within the SIMULATION block which for convenience, should be located at the top of the input file (but this is not required). Cards within the SIMULATION block include:

SIMULATION
Opens the SIMULATION block.
SIMULATION_TYPE <string>

Defines the domain to be modeled and the types of process models employed. Options include:

SUBSURFACE

SURFACE_SUBSURFACE

HYDROGEOPHYSICS

PROCESS_MODELS

Opens a block for defining all process models employed. At this point, the ordering and linkage of these process models is preset. For instance, SUBSURFACE_FLOW processes always precede SUBSURFACE_TRANSPORT processes in timestep execution. Options include:

SUBSURFACE_FLOW

SUBSURFACE_TRANSPORT

SURFACE_FLOW

CHECKPOINT
Opens a block for specifying checkpointing parameters.
RESTART
Specifies name of restart files and time at which to restart if different from checkpoint time.
SUBSURFACE
Opens a block of input parameters for subsurface process models (this block is essentially, the old PFLOTRAN input file with the exception that several of the cards (i.e. flow MODE) have been moved to the SIMULATION block.
END_SUBSURFACE
Closes the subsurface block.

SUBSURFACE keywords (Look here for all subsurface keywords, essentially most of the old input guide keywords.)

## Examples

SIMULATION
SIMULATION_TYPE SUBSURFACE
PROCESS_MODELS
SUBSURFACE_FLOW flow
...
/
SUBSURFACE_TRANSPORT transport
...
/
/
CHECKPOINT
PERIODIC TIMESTEP 10
TIMES y 10.
FORMAT HDF5
/
RESTART restart.chk 0.
END

SUBSURFACE
...
END_SUBSURFACE


Updated