Output Control Card Options (W)

Two types of output can be requested in the output control card:

1. Reference Node output 
2. Plot File output

Reference Node Output

Reference node output is generated by selecting reference nodes, or grid cells, and output variables. The user may request any number of reference nodes, but reference node output was primarily designed for tracking the time evolution of selected variables at key points of interest. Reference nodes are defined with three indices, which indicate the x-, y-, and z-direction coordinates of the grid cell. Grid cell numbering in the simulator increments in the order i, j, and k, where the indices refer to the x-, y-, and z-directions, respectively for Cartesian coordinate systems, and r-, θ-, and z-directions, respectively, for cylindrical coordinate systems. Reference Node Screen Output Frequency and Reference Node Output File Frequency are parameters that indicate how often, with respect to the time step, reference node output will be written to STDIO and the output file, respectively. A frequency value of 1 indicates reference node output occurs every time step, whereas a frequency value of 10 indicates that reference node output occurs every 10 time steps. The user has control over the output time and length units and the number of significant digits reported to the various output media. Unless declared through the Output Time Units or Output Length Units input items, values for time and lengths recorded to the output media will be expressed in units of seconds and meters, respectively. These inputs allow the user to customize time- and length-scale units to those most appropriate to the solved problem. The Screen Significant Digits, Output File Significant Digits, and Plot File Significant Digits input items allow the user to customize the number of significant digits that appear in field and flux variable results written to the STDIO, output file, and plot.n file, respectively. The default value for the number of significant digits is 5, and the minimum number of significant digits is 4. Output units for all dimensional variables can be specified immediately following the variable name. Variables without units require a null entry for the variable units. Null entries for variables with units yield default output units, which are expressed in SI units. The output file can be converted for plotting using the outputTo.pl perl script utility.

Variables that can be specified for reference node output are shown in the Reference Node Variable List.

Plot File Output

Plot files are written at the conclusion of an execution, by default, and at each requested Plot File Output Time. Plot files contain geometry data and selected field and flux variable results for every node in the computational domain. These files represent a “snapshot” of the simulation at a certain point in time. Requests for Plot File Output Times can be specified with user defined units. A restart.n file is generated with every plot.n file. Both restart.n and plot.n files are suffixed with a file name extension of a dot followed by an integer (e.g., plot.567, restart.0032). The extension integer corresponds with the time step for which the file was written. Both plot.n and restart.n files are written at the conclusion of a time step. Field and flux variables recorded to plot.n files are selected from the Plot File Variable List. Output units for all variables with units can be specified in the input item immediately following the variable name. Variables without units require a null entry for the variable units. Null entries for variables with units yield default output units, which are expressed in SI units. The plot.n files can be converted for plotting using the plotTo.pl perl script utility.

Variables that can be specified for plot file output are shown in the Plot File Variable List.

Additional Output for Reactive Transport

For Reactive Transport modules, the Output Control Card allows for reactive species output to the output and plot.n files. Reactive species output in Reference Node or Plot File forms is specified in the same manner as solute output, with the exception that the keyword Species is used instead of Solute. Required input includes the output variable, species name, and output units. Species variables that can be specified for reference node output are shown in the ECKEchem Reference Node Species Variable List, and variables that can be specified for plot file output are shown in the ECKEChem Plot File Species Variable List.