Source Card Description (G)

Overview

This card allows the user to control sources and/or sinks of mass, energy, and solutes by defining time-varying sources.  This card also allows for sources to be specified for reactive species.  Reactive species sources are specified in the same manner as solute sources, using a species rate (i.e., mol/s).  Required input includes the source type, species name, source domain, the number of time points, and for each time point: the time, and species source rate and units.

By definition, sinks are negative sources, and sources refer to an influx of mass, energy, or solute into a node.  Sources can be specified for interior or boundary nodes and are functionally analogous to Neumann type boundary conditions.  Sources applied to inactive nodes are not recognized.  Sources are time varying; however, unlike boundary conditions, multiple sources may be applied to a node during the same time period.  The simulator controls time steps to agree with time transitions in sources.

Sinks

Sinks withdraw mass or solutes from a node.  The physical properties of the fluids withdrawn through sinks are the same as the properties of the fluids at the source node location.  Solute sinks withdraw solute mass in the assumed units for solute (e.g., Ci, pCi, gm, kg, mol, kmol).

Sources

Sources inject mass or solutes into a node.  The physical properties for fluids injected through sources are computed from the specified input parameters.  Solute sources inject solute mass in the assumed units for solute (e.g., Ci, pCi, gm, kg, mol, kmol).

Time Variations

Time variations of sources are controlled through declaring multiple source times.  All Source Time inputs are referenced against the Initial Time specified in the Solution Control Card or obtained from a restart file.  A source declared with a single Source Time implies that the source is time invariant and the specified Source Time represents the start time for the source.  Prior to the start time, the source will be zero, and from the start time to execution completion the source will be as specified.  If a source is declared with multiple Source Times, then the first time listed equals the start time, the last time listed equals the stop time, and the intermediate times are transition points.  For simulation times outside of the start and stop time limits, zero source conditions apply.  For simulation times between two Source Times, linear interpolation of the sources is applied.  Step source changes can be simulated by defining duplicate Source Times, where the first time would indicate the completion of the previous source, and the second time would indicate the start of the new source.  At the completion of the step source, another set of duplicate Source Time declarations would be used.  Step sources are convenient methods to introduce slugs of fluids or solute into an interior node.