Output Control Card Options (HYDT-KE)

Two types of output can be requested in the output control card: 1) Reference Node output and 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 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. The same list of variables for each operational mode is available for output to the plot.n files. Output units for all variables with units 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.  Variables that can be specified for reference node output are shown in the table below.

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 list shown below. 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.