The Generalized Flow pane is on the Sutra Features tab of the Object Properties dialog box. It is used to specify Generalized Flow boundaries in SUTRA 3.0.
The Generalized Flow pane is only visible if Evaluated at is set to Nodes.
The Schedule (BCSSCH) combobox is used to select a time schedule and a table where the boundary condition values are defined. The user can select Custom as the time schedule. With a Custom time schedule, the user can specify any time in the boundary condition table. Otherwise, only times defined in the time schedule can be selected.
The table on Generalized Flow pane has the following columns
Time defines when the boundary condition changes.
Used (IPBG1) is used to define a formula that will determine whether boundary condition on or off. Different formulas can be used at different times to control the nodes to which the boundary condition applies.
Pressure 1 (PBG11) Pressure value at the first of two points that define the linear relation between fluid inflow/outflow and pressure at node IPBG. [M/(L∙s2)]. Pressure 2 must be greater than Pressure 1.
Flow 1 (QPBG11) Rate of inflow/outflow of fluid mass when the computed pressure equals PBG1 at node IPBG. [M/s]. Flow 2 must be less than Flow 1.
Pressure 2 (PBG21) Pressure value at the second of two points that define the linear relation between fluid inflow/outflow and pressure at node IPBG. [M/(L∙s2)]. Pressure 2 must be greater than Pressure 1.
Flow 2 (QPBG21) Rate of inflow/outflow of fluid mass when the computed pressure equals PBG2 at node IPBG. [M/s]. Flow 2 must be less than Flow 1.
Limit 1 (CPQL11) Determines whether a limit is set on fluid inflow/outflow, pressure, or neither at the first of two points that define the linear relation between fluid inflow/outflow and pressure at node IPBC. [M/(L∙s2)].
Limit 2 (CPQL21) Determines whether a limit is set on fluid inflow/outflow, pressure, or neither at the second of two points that define the linear relation between fluid inflow/outflow and pressure at node IPBC.
Inflow U (UPBGI1) Temperature or solute concentration of any external fluid that enters the model at node IPBC. UPBGI is a specified constant value. [°C] or [Ms/M].
Outflow U Specification Method (CPBGO1) specifies whether Outflow U is an absolute value or a difference in value relative to the concentration at the nodel. Indicates whether the temperature or solute concentration, UPBGO, of any fluid that exits the model at node IPBG is being specified directly (‘DIR’) or relative to the computed concentration or temperature at the node (‘REL’)
Outflow U (UPBGO1) Temperature or solute concentration of any fluid that exits the model at node IPBG. If CUPBGO = ’DIR’, the exit temperature or concentration is set directly to the value UPBGO. If CUPBGO = ’REL’, the exit temperature or concentration is set to the value U+UBPGO, where U is the temperature or concentration computed at the node. [°C] or [Ms/M].
If neither Limit 1 nor Limit 2 are specified, the generalized flow boundary is analogous to the General Head Boundary in MODFLOW.
If Limit 1 is specified and Flow 1 is zero, the generalized flow boundary is analogous to the Drain package in MODFLOW.
If Limit 1 is specified and Flow 1 is greater than zero, the generalized flow boundary is analogous to the River package in MODFLOW.
If Limit 1 and Limit 2 are both specified and Flow 1 is zero, the generalized flow boundary is analogous to the Evapotranspiration package in MODFLOW.
If the user wishes to program the subroutine BCTIME in SUTRA, the Use BCTime checkbox can be used to specify which nodes have their values set via BCTIME.
For SUTRA 3.0 models in which lakes are used, If Lake water present of absent and Interaction type can be used to override the values selected on the Lake-Boundary Interaction pane of the SUTRA Options dialog box. If Use defaults is selected, the value from the Lake-Boundary Interaction pane will be used.
For more information on the Generalized Flow boundary condition, see the SUTRA 3.0 documentation.
