You may select from the transport boundary conditions listed below.
No solute flux. The solute mass flux across the boundary is zero. This boundary condition is available only for boundary segments that are assigned a "no flow" boundary condition.
Specified concentration at boundary. The solute concentration at the boundary is set at the specified value. In the model, this is implemented by setting the concentration at boundary cells to the specified value.
Specified concentration of inflow. The concentration of flow across the boundary into the domain is set at the specified value. This boundary condition effectively sets the solute mass flux across the boundary into the domain. This mass flux is equal to the inflow concentration times the fluid flux.
Specified diffusive flux at boundary. The flux of solute by diffusion across the boundary into the domain (in units of [M/LT]) is set at the specified value. This boundary condition is available only for boundary segments that are assigned a "no flow" boundary condition.
Default outflow. This boundary condition must be specified along boundaries of possible seepage faces, evaporation/transpiration, and where flux or volumetric flow rate is specified in the direction out of the domain. For all the above cases except evaporation, the solute flux out of the domain is computed by multiplying the concentration at boundary cell with the outflow flux (dispersive flux out of the domain is not allowed). For evaporation, the evaporating water is assumed to be solute free.
Transport Boundary Condition Options
For any boundary segment, the available options for transport boundary conditions depend on the flow boundary condition specified for that segment.
For boundary segments that are assigned "no flow" boundary condition, the options for transport boundary conditions are:
For boundary segments that are assigned flow boundary conditions of "specified pressure head", "specified total head", "specified flux into domain", or "specified volumetric flow into domain", the options for transport boundary conditions are:
For boundary segments that are assigned flow boundary conditions of "specified flux out of domain", "specified volumetric flow out of domain", "evaporation/transpiration", or "possible seepage face", the sole option for transport boundary condition is:
See also:
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