FLOW_CONDITION¶

Sets flow parameters used in setting up flow boundary and initial conditions and source/sinks.

Required Cards:¶

FLOW_CONDITION <string>: Opens the FLOW_CONDITION block, where <string> is the assigned name of the condition so that it can be referred to in cards BOUNDARY_CONDITION, INITIAL_CONDITION, or SOURCE_SINK.
TYPE: Opens the TYPE sub-block. Within this sub-block, the type of the flow condition is specified. Options for TYPE are specific to which mode you are running in.

TYPE specification in RICHARDS and TH flow modes¶

TYPE
[LIQUID_PRESSURE {DIRICHLET, HYDROSTATIC, SEEPAGE, CONDUCTANCE, DIRICHLET_SEEPAGE, DIRICHLET_CONDUCTANCE}, RATE {MASS_RATE, VOLUMETRIC_RATE, SCALED_MASS_RATE, SCALED_VOLUMETRIC_RATE}, LIQUID_FLUX {NEUMANN}, TEMPERATURE {DIRICHLET}, ENERGY_RATE {ENERGY_RATE, SCALED_ENERGY_RATE}, ENERGY_FLUX {NEUMANN}]

LIQUID_PRESSURE DIRICHLET: specifies a fixed pressure across the entire condition.

LIQUID_PRESSURE HYDROSTATIC: specifies a hydrostatic condition where a hydrostatic pressure profile is assigned based on the defined DATUM (and GRADIENT, if applicable) and the function rho*g*h where rho is water density, g is gravity and h is the distance from the DATUM. Note that the water density is incrementally updated as the algorithm moves above or below the DATUM at which the assigned pressure and temperature are defined.

LIQUID_PRESSURE SEEPAGE: a seepage face condition is similar to a hydrostatic, EXCEPT that flow may only come into the domain when the boundary face pressure is above a user defined reference pressure. The flow out of the domain is unmodified and is possible at all times. The default reference pressure is atmospheric pressure (101325 Pa).

LIQUID_PRESSURE CONDUCTANCE: the conductance type condition is designed to mimic a lower permeability soil layer at the boundary of a domain (e.g. a mud layer at the bottom of a river). A conductance condition is similar to a seepage face, EXCEPT that a conductance term (permeability/distance) is specified through a CONDUCTANCE keyword. The permeability of the boundary grid cell and its size (i.e. distance from cell center to boundary) no longer matter. The conductance coefficient is a fit parameter.

LIQUID_PRESSURE DIRICHLET_SEEPAGE: a dirichlet-seepage condition is similar to seepage, except a specified dirichlet pressure is applied at the boundary instead of sampling pressure from a hydrostatic profile. Inflow only occurs when the specified pressure is higher than the reference pressure.

LIQUID_PRESSURE DIRICHLET_CONDUCTANCE: a dirichlet-conductance condition is similar to conductance, except a specified dirichlet pressure is applied at the boundary instead of sampling pressure from a hydrostatic profile. Inflow only occurs when the specified pressure is higher than the reference pressure.

LIQUID_FLUX NEUMANN: specifies a Darcy flux.

RATE MASS_RATE: specifies a mass extraction/injection rate.

RATE VOLUMETRIC_RATE: specifies a volumetric extraction/injection rate.

RATE SCALED_MASS_RATE <string>: specifies an extraction/injection rate scaled/distributed among grid cells in the coupled region, where <string> is one of the scaling options below.

RATE SCALED_VOLUMETRIC_RATE <string>: specifies a volumetric extraction/injection rate scaled/distributed among grid cells in the coupled region, where <string> is one of the scaling options below.

ENERGY_RATE ENERGY_RATE: specifies an energy extraction/injection rate.

ENERGY_RATE SCALED_ENERGY_RATE: specifies an energy extraction/injection rate scaled/distributed among grid cells in the coupled region, where <string> is one of the scaling options below. Note that in this case, the VOLUME scaling option makes the most sense.

TYPE specification in GENERAL flow mode¶

TYPE
[LIQUID_PRESSURE {DIRICHLET, HYDROSTATIC, SEEPAGE, CONDUCTANCE}, GAS_PRESSURE {DIRICHLET}, LIQUID_SATURATION {DIRICHLET}, GAS_SATURATION {DIRICHLET}, TEMPERATURE {DIRICHLET}, MOLE_FRACTION {DIRICHLET}, RELATIVE_HUMIDITY {DIRICHLET}, LIQUID_FLUX {NEUMANN}, GAS_FLUX {NEUMANN}, ENERGY_FLUX {NEUMANN}, RATE {MASS_RATE, SCALED_MASS_RATE}]

LIQUID_PRESSURE DIRICHLET: specified a fixed pressure. Note that HYDROSTATIC can be used, but only within the saturated zone (liquid phase state only).

GAS_PRESSURE DIRICHLET: specifies a fixed gas pressure (two-phase and gas state only).

LIQUID_SATURATION DIRICHLET: specifies a liquid phase saturation (two phase state only).

GAS_SATURATION DIRICHLET: specifies a gas phase saturation (two phase state only).

TEMPERATURE DIRICHLET: specifies a temperature.

ENERGY_FLUX NEUMANN: specifies an energy flux.

LIQUID_FLUX NEUMANN: specifies a liquid phase Darcy flux.

GAS_FLUX NEUMANN: specifies a gas phase Darcy flux.

RELATIVE_HUMIDITY DIRICHLET: specifies a relative humidity from which an air partial pressure will be calculated (gas phase state only).

MOLE_FRACTION DIRICHLET: specifies the air mole fraction in the gas or liquid phase (liquid and gas phase states only).

RATE MASS_RATE: specifies a mass extraction/injection rate. Note that this actually applies to energy too.

RATE SCALED_MASS_RATE <string>: specifies an extraction/injection rate scaled/distributed among grid cells in the coupled region, where <string> is one of the scaling options below. Note that this actually applies to energy too.

Initial thermodynamic states for combinations of Dirichlet-based conditions:

GAS_PRESSURE + GAS_SATURATION = two-phase state,

LIQUID_PRESSURE + MOLE_FRACTION = single-phase liquid state,

GAS_PRESSURE + (MOLE_FRACTION | RELATIVE_HUMIDITY) = single-phase gas state

GENERAL mode flow conditions must include a TEMPERATURE and a MOLE_FRACTION/RELATIVE_HUMIDITY or GAS_SATURATION/LIQUID_SATURATION (but not both LIQUID_SATURATION and a MOLE_FRACTION/RELATIVE_HUMIDITY).

TYPE specification in HYDRATE flow mode¶

TYPE
[LIQUID_PRESSURE {DIRICHLET, HYDROSTATIC, SEEPAGE, CONDUCTANCE}, GAS_PRESSURE {DIRICHLET, HYDROSTATIC (advanced)}, LIQUID_SATURATION {DIRICHLET}, GAS_SATURATION {DIRICHLET}, HYDRATE_SATURATION {DIRICHLET}, ICE_SATURATION {DIRICHLET} TEMPERATURE {DIRICHLET}, MOLE_FRACTION {DIRICHLET}, RELATIVE_HUMIDITY {DIRICHLET}, LIQUID_FLUX {NEUMANN}, GAS_FLUX {NEUMANN}, ENERGY_FLUX {NEUMANN}, RATE {MASS_RATE, SCALED_MASS_RATE}]

LIQUID_PRESSURE DIRICHLET: specified a fixed pressure. Note that HYDROSTATIC can be used, but only within the saturated zone or in 2-phase gas-aqueous with very low gas saturation, an advanced feature.

GAS_PRESSURE DIRICHLET: specifies a fixed gas pressure. When a gas phase is not present, gas pressure and liquid pressure can be used interchangeably.

LIQUID_SATURATION DIRICHLET: specifies a liquid phase saturation.

GAS_SATURATION DIRICHLET: specifies a gas phase saturation.

HYDRATE_SATURATION DIRICHLET: specifies a gas hydrate phase saturation.

ICE_SATURATION DIRICHLET: specifies a ice phase saturation.

TEMPERATURE DIRICHLET: specifies a temperature.

ENERGY_FLUX NEUMANN: specifies an energy flux.

LIQUID_FLUX NEUMANN: specifies a liquid phase Darcy flux.

GAS_FLUX NEUMANN: specifies a gas phase Darcy flux.

RELATIVE_HUMIDITY DIRICHLET: specifies a relative humidity from which an air partial pressure will be calculated (gas phase state only).

MOLE_FRACTION DIRICHLET: specifies the air mole fraction in the liquid or gas phase.

RATE MASS_RATE: specifies a mass extraction/injection rate. Note that this actually applies to energy too.

RATE SCALED_MASS_RATE <string>: specifies an extraction/injection rate scaled/distributed among grid cells in the coupled region, where <string> is one of the scaling options below. Note that this actually applies to energy too.

Initial thermodynamic states for combinations of Dirichlet-based conditions:

Aqueous State: LIQUID_PRESSURE + MOLE_FRACTION + TEMPERATURE

Gas State: GAS_PRESSURE + (MOLE_FRACTION | RELATIVE_HUMIDITY) + TEMPERATURE

Hydrate State (can be unstable): GAS_PRESSURE + TEMPERATURE

Ice State (can be unsable): GAS_PRESSURE + TEMPERATURE

Gas-Aqueous State: GAS_PRESSURE + GAS_SATURATION + TEMPERATURE

Hydrate-Gas State: GAS_PRESSURE + GAS_SATURATION + TEMPERATURE

Hydrate-Aqueous State: GAS_PRESSURE + HYDRATE_SATURATION + TEMPERATURE

Hydrate-Ice State: GAS_PRESSURE + HYDRATE_SATURATION + TEMPERATURE

Gas-Ice State: GAS_PRESSURE + ICE_SATURATION + TEMPERATURE

Aqueous-Ice State: LIQUID_PRESSURE + MOLE_FRACTION + LIQUID_SATURATION

Hydrate-Gas-Aqueous State: LIQUID_SATURATION + HYDRATE_SATURATION +
TEMPERATURE

Hydrate-Gas-Ice State: ICE_SATURATION + HYDRATE_SATURATION + TEMPERATURE

Gas-Aqueous-Ice State: GAS_PRESSURE + LIQUID_SATURATION + ICE_SATURATION

Hydrate-Gas-Aqueous-Ice State: LIQUID_SATURATION + GAS_SATURATION +
ICE_SATURATION

TYPE specification in WIPP_FLOW flow mode¶

TYPE
[LIQUID_PRESSURE {DIRICHLET}, LIQUID_SATURATION {DIRICHLET}, GAS_SATURATION {DIRICHLET}, LIQUID_FLUX {NEUMANN}, GAS_FLUX {NEUMANN}, RATE {MASS_RATE, SCALED_MASS_RATE

LIQUID_PRESSURE DIRICHLET: specified a fixed pressure.

LIQUID_SATURATION DIRICHLET: specifies a liquid phase saturation

GAS_SATURATION DIRICHLET: specifies a gas phase saturation

LIQUID_FLUX NEUMANN: specifies a liquid phase Darcy flux.

GAS_FLUX NEUMANN: specifies a gas phase Darcy flux.

RATE MASS_RATE: specifies a mass extraction/injection rate.

RATE SCALED_MASS_RATE <string>: specifies an extraction/injection rate scaled/distributed among grid cells in the coupled region, where <string> is one of the scaling options below.

RATE Scaling Options:¶

PERM: scaling weighted as a function of cell volume and X permeability

NEIGHBOR_PERM: scaling weighted as a function of the interfacial area and permeability of neighboring cells (in x,y)

VOLUME: scaling weighted as a function of cell volume

Value specification for all flow modes:¶

For each TYPE option specified in the TYPE sub-block described above, a corresponding type-value card must be included that specifies the value of the TYPE. The possible type-value cards include:

PRESSURE <float>

The pressure [Pa] applied at the boundary.

LIQUID_PRESSURE <float>

The liquid pressure [Pa] applied at the boundary.

GAS_PRESSURE <float>

The gas pressure [Pa] applied at the boundary.

FLUX <float>

The Darcy flux [m/s] applied to the boundary. Positive flux is inward, negative outward, regardless of the direction of the boundary connection.

LIQUID_FLUX <float>

The liquid Darcy flux [m/s] applied to the boundary. Positive flux is inward, negative outward, regardless of the direction of the boundary connection.

GAS_FLUX <float>

The gas Darcy flux [m/s] applied to the boundary. Positive flux is inward, negative outward, regardless of the direction of the boundary connection.

TEMPERATURE <float>

The temperature [C] applied at the boundary.

ENERGY_FLUX <float>

The energy flux [MW/m²] applied to the boundary. Positive flux is inward, negative outward, regardless of the direction of the boundary connection.

RELATIVE_HUMIDITY <float>

The relative humidity in percent [-] applied at the boundary.

RATE <float> [<float> [<float>]]

Injection/extraction rate in kg/s (mass) or m³/s (volumetric). Positive in, negative out. For WIPP_FLOW mode, the rate is by component (i.e. water component [kg/s], air component [kg/s]) For GENERAL mode, the rate is by component and energy (i.e. water component [kg/s], air component [kg/s], energy [MW]).

A list or external file may be used instead of specifying a float using the keywords: LIST or FILE <string>. To do so, one must provide an external file with a Rank One Array Specification or a Rank Three Array Specification.

LIQUID_SATURATION <float>

The liquid saturation [-] applied at the boundary.

GAS_SATURATION <float>

The gas saturation [-] applied at the boundary.

MOLE_FRACTION <float>

The gas mole fraction [-] applied at the boundary.

A list or external file may be used instead of specifying a float using the keywords: LIST or FILE <string>. To do so, one must provide an external file with a Rank One Array Specification

Optional Cards:¶

DATUM <float float float>

Reference X,Y, Z coordinate for defining the flow condition. E.g. If type is LIQUID_PRESSURE HYDROSTATIC, the datum coordinate is where the LIQUID_PRESSURE value is set, and other pressures in the hydrostatic condition are calculated in the vertical and horizontal (if a GRADIENT is defined) based on that reference point.

An external file may be used instead of specifying floats using the keywords: FILE <string>. To do so, one must provide an external file with a Rank Three Array Specification.

GRADIENT

Opens a block defining a pressure or temperature gradient based on the datum coordinate.

An external file may be used instead of specifying floats using the keywords: FILE <string>. To do so, one must provide an external file with a Rank Three Array Specification.

LIQUID_PRESSURE <float float float>

When the Z value is zero (0.),: Specifies the unitless head gradient in the x and y directions through the gradient plane <dh/dx, dh/dy> [m/m]
When the Z value is nonzero,: Specifies a pressure gradient in x y z <dp/dx, dp/dy, dp/dz> [Pa/m].

TEMPERATURE <float float float>

Specifies the temperature gradient in the x y z <dT/dx, dT/dy, dT/dz> [C/m].

INTERPOLATION <string>

Interpolation scheme used to calculate transient update, where the options for <string> include: [LINEAR, STEP (default)].

CYCLIC

Cycles a transient data set back to initial value when maximum data set time is exceeded, repeatedly cycling through the data.

SYNC_TIMESTEP_WITH_UPDATE

Forces waypoints to be set for each time in a timeseries forcing time stepping to match the waypoints.

CONDUCTANCE <float>

Conductance coefficient used when a conductance condition is specified.

STATE <string>

For HYDRATE mode, specify the state of the flow condition. This is necessary for ice state (I), hydrate state (H), hydrate-ice (HI), hydrate-gas (HG), and hydrate-aqueous-ice (HAI).

Examples¶

RICHARDS Mode Examples¶

FLOW_CONDITION Initial
  TYPE
    LIQUID_PRESSURE HYDROSTATIC
  /
  DATUM 0.d0 0.d0 105.016d0
  GRADIENT
    LIQUID_PRESSURE -1.9542d-4 1.4240d-4 0.d0
  /
  LIQUID_PRESSURE 101325.d0
/

FLOW_CONDITION Piezometric_Surface
  TYPE
    LIQUID_PRESSURE HYDROSTATIC
  /
  CYCLIC
  DATUM FILE ./A_datum_2008.txt
  GRADIENT
    LIQUID_PRESSURE FILE ./A_gradient_2008.txt
  /
  LIQUID_PRESSURE 101325.d0
/

FLOW_CONDITION Recharge
  TYPE
    LIQUID_FLUX NEUMANN
  /
  LIQUID_FLUX 1.757d-9 ! [m/s]
/

FLOW_CONDITION injection
  TYPE
    RATE SCALED_VOLUMETRIC_RATE NEIGHBOR_PERM
  /
  RATE 1 m^3/day
/

FLOW_CONDITION injection
  TYPE
    RATE SCALED_VOLUMETRIC_RATE
  /
  RATE FILE transient_rate.txt
/

FLOW_CONDITION injection
  TYPE
    RATE SCALED_VOLUMETRIC_RATE
  /
  : to inject at 2 m^3/day between days 10-15.
  SYNC_TIMESTEP_WITH_UPDATE
  RATE LIST
    TIME_UNITS day
    DATA_UNITS m^3/day
    0. 0.
    10. 2.
    15. 0.
  /
/

! Distributes a mass rate of 0.02 kg/day across all grid cells in region, scaled
! by fraction cell volume / total volume
FLOW_CONDITION injection
  TYPE
    RATE SCALED_MASS_RATE VOLUME
  /
  RATE 2.d-2 kg/day
END

TH Mode Examples¶

FLOW_CONDITION initial
  TYPE
    LIQUID_PRESSURE DIRICHLET
    TEMPERATURE DIRICHLET
  /
  LIQUID_PRESSURE 1.D5
  TEMPERATURE DATASET Temperature
END

FLOW_CONDITION recharge
  TYPE
    LIQUID_FLUX NEUMANN
    TEMPERATURE DIRICHLET
  /
  LIQUID_FLUX 10 cm/y
  TEMPERATURE 25.D0
END

GENERAL Mode Examples¶

FLOW_CONDITION Liquid
  TYPE
    LIQUID_PRESSURE DIRICHLET
    MOLE_FRACTION DIRICHLET
    TEMPERATURE DIRICHLET
  /
  LIQUID_PRESSURE 2.d5
  MOLE_FRACTION 1.d-8
  TEMPERATURE 25.d0
/

FLOW_CONDITION Two_Phase
  TYPE
    GAS_PRESSURE DIRICHLET
    GAS_SATURATION DIRICHLET
    TEMPERATURE DIRICHLET
  /
  GAS_PRESSURE 2.d5
  GAS_SATURATION 0.25d0
  TEMPERATURE 25.d0
/

FLOW_CONDITION east_face
  TYPE
    TEMPERATURE DIRICHLET
    LIQUID_PRESSURE DIRICHLET
    MOLE_FRACTION DIRICHLET
  /
  TEMPERATURE DATASET temperature_bc_east
  LIQUID_PRESSURE 101325 Pa
  MOLE_FRACTION 1.d-20
END

FLOW_CONDITION Two_Phase ! alternate
  TYPE
    GAS_PRESSURE DIRICHLET
    LIQUID_SATURATION DIRICHLET
    TEMPERATURE DIRICHLET
  /
  GAS_PRESSURE 2.d5
  LIQUID_SATURATION 0.75d0
  TEMPERATURE 25.d0
/

FLOW_CONDITION west_face
  TYPE
    ENERGY_FLUX NEUMANN
    LIQUID_FLUX NEUMANN
    GAS_FLUX NEUMANN
  /
  ENERGY_FLUX -1.0d0 W/m^2
  LIQUID_FLUX 0.d0 m/yr
  GAS_FLUX 0.d0 m/yr
END

FLOW_CONDITION Gas
  TYPE
    GAS_PRESSURE DIRICHLET
    MOLE_FRACTION DIRICHLET
    TEMPERATURE DIRICHLET
  /
  GAS_PRESSURE 2.d5
  MOLE_FRACTION 0.01d0
  TEMPERATURE 25.d0
/

FLOW_CONDITION Gas2
  TYPE
    GAS_PRESSURE DIRICHLET
    RELATIVE_HUMIDITY DIRICHLET
    TEMPERATURE DIRICHLET
  /
  GAS_PRESSURE 2.d5
  RELATIVE_HUMIDITY 50 ! in percent
  TEMPERATURE 25.d0
/

! example for an source/sink injection well
FLOW_CONDITION well
  TYPE
    RATE mass_rate
  /
     ! liquid gas   energy
  RATE 0.d0   1.d-5 0.d0 kg/s kg/s MW
/

FLOW_CONDITION left_end
  TYPE
    TEMPERATURE DIRICHLET
    LIQUID_PRESSURE DIRICHLET
    MOLE_FRACTION DIRICHLET
  /
  TEMPERATURE LIST
    # T = Tb*t; Tb=2C
    TIME_UNITS day
    DATA_UNITS C
    INTERPOLATION LINEAR
    #time  #temperature
    0.00d0 0.0d0
    0.25d0 0.5d0
    0.50d0 1.0d0
    1.00d0 2.0d0
  /
  LIQUID_PRESSURE 101325 Pa
  MOLE_FRACTION 1.d-10
END

HYDRATE Mode Examples¶

#HYDRATE-AQUEOUS State Flow Condition
FLOW_CONDITION initial
  TYPE
    LIQUID_PRESSURE DIRICHLET
    HYDRATE_SATURATION DIRICHLET
    TEMPERATURE DIRICHLET
  /
  LIQUID_PRESSURE 1.d7
  HYDRATE_SATURATION 2.d-1
  TEMPERATURE 5.d0
END

#AQUEOUS-ICE State Flow Condition
FLOW_CONDITION initial
  TYPE
    LIQUID_PRESSURE DIRICHLET
    MOLE_FRACTION DIRICHLET
    LIQUID_SATURATION DIRICHLET
  /
  LIQUID_PRESSURE 1.d6
  MOLE_FRACTION 1.d-5
  LIQUID_SATURATION 9.d-1
END

#HYDRATE-AQUEOUS-ICE State Flow Condition
FLOW_CONDITION initial
  TYPE
    LIQUID_PRESSURE DIRICHLET
    LIQUID_SATURATION DIRICHLET
    ICE_SATURATION DIRICHLET
  /
  LIQUID_PRESSURE 1.d7
  LIQUID_SATURATION 6.5d-1
  ICE_SATURATION 3.d-1
  STATE HAI
END

WIPP_FLOW Mode Examples¶

FLOW_CONDITION INITIAL
  TYPE
    LIQUID_PRESSURE DIRICHLET
    LIQUID_SATURATION DIRICHLET
  END
  LIQUID_PRESSURE 1.280390d5
  LIQUID_SATURATION 6.5d-1
END