4 - 13   FLUENT Loader

The FLUENT^® Data Loader reads FLUENT Version 5 and newer case (.cas) and data (.dat) files up to and including version 14.0. To load files from earlier versions of FLUENT, you must first import them into FLUENT 5 or newer, then resave them in the newer format.

Particle data may also be loaded from an accompanying XML file. If loading a single .dat/.cas pair, all sections of particle data in an accompanying XML file are loaded. If loading multiple .dat/.cas pairs, one particle section is loaded from the XML file for each .dat/.cas pair loaded. If the XML file is invalid, particle data will be skipped, but the rest of the data will continue to be loaded.

When possible, and assuming the user has the necessary permissions to create new files in the directory containing the FLUENT files, the FLUENT loader creates an index file for each case and data file it loads. These files are stored in a subdirectory called tecplot-derived located in the same directory as the case and data files and are used to load the data faster in future sessions. The FLUENT loader assumes that any files it finds in the tecplot-derived directory relate to the case and data files found in the parent directory. If the FLUENT data files are updated, delete the files in the tecplot-derived directory so that the FLUENT loader will regenerate them. (Be sure all Tecplot 360 EX sessions using the files are closed first.)

Tecplot 360 EX does not automatically calculate CFD variables from your existing FLUENT data variables. You may add the variables to your plots by performing calculations via the Analyze menu. Refer to Chapter 21: “CFD Data Analysis” for details.

Additionally, Tecplot 360 EX does not perform the same wall-boundary calculations that are performed by FLUENT. Instead, the cell-centered data will be extrapolated to the boundary.

See also Section 7 - 2 “Time Aware” for information on working with transient datasets in Tecplot 360 EX.

The following options are available:

• Load Case and Data Files - Loads both a case and a data file. The grid comes from the case file, and the solution comes from the data file.

• Load Case File Only - Loads the grid from a case file.

• Load Residuals Only - Loads the residual data (convergence history) from a data file. The residuals are not scaled or normalized.

• Load Multiple Case and Data Files [DEFAULT] - Displays the File List form in the dialog. You can load matched pairs of case and data files, or one case file and any number of data files that match it (that is, that have the same zones).

For all load options above, except Load Multiple Case and Data Files, the following controls are available:

• Case File - Type the name of the case file you wish to load, or click [Select], then select the name of the file from the resulting dialog.

• Data File - The data (.dat) file contains the solution and the residual (convergence history) data. Type the name of the data file, or click Select, then select the name of the file from the resulting dialog.

For the Load Multiple Case and Data Files load option, the following controls are available:

• Add Files - Choose case and data files to load from a file selection dialog. Selected files are appended to the file list.

• Remove - Remove files you have selected in the file list.

• Remove All - Remove all files in the file list.

• Flow is Unsteady - Indicates that the set of case and data files represents an unsteady solution. The loader adds a TIME auxiliary data item to each loaded zone. Tecplot 360 EX does not use this data, but other add-ons may.

• Flow Solution is Unsteady/Time Interval - The FLUENT data loader saves the problem time of each solution as the solution time variable. There are two options for determining the time to save for each one: (1) reading the flow-time entry from each .dat file, or (2) applying a constant time interval to successive .dat files.

• Read Time from Data Files - If this option is selected, Tecplot 360 EX reads the flow-data parameter from each .dat file. If no .dat files are included (i.e. only .cas files are loaded), the solution time variable will not be created for the zones.

• Apply Constant Time Interval - If this option is selected, Tecplot 360 EX applies the time interval specified in the Time Interval text field to zones created from successive .cas or .dat files. The zones from the first .cas/.dat files are given time 0. Times for successive files are calculated by incrementing the time of the previous files by the specified time interval.

• Assign Strand IDs for Zones - Toggle-on to have Tecplot 360 EX assign Strand IDs to transient zones. Common strand IDs will be assigned to each cell or boundary zone with matching FLUENT zone IDs.

• Add Zones to existing Strands - Toggle-on to add the appended zones to StrandIDs in the current dataset.

• Time Interval - If "Apply Constant Time Interval" is selected, the time interval entered in the text field is included.

For the load options other than Load Residuals, some or all of the following controls are available:

• Load Cells and Boundaries - Loads the cell (solution) and boundary zones from the case file. Each fluid or solid cell zone and each boundary zone will be displayed as a separate zone in Tecplot 360 EX.

• Load Cells Only - Loads only the cell (solution) zones. Each zone will be displayed as a separate zone in Tecplot 360 EX.

• Load Boundaries Only - Loads only the boundary zones. Each zone will be displayed as a separate zone in Tecplot 360 EX.

• Select Zones and Variables to Load - Select in a separate dialog which zones and variables to load. The option requires the loader to pre-scan all files, which can be time-consuming.

• Create All Zones As Polyhedral - Select this option to load all FLUENT zones as Tecplot 360 EX polytope (polygonal or polyhedron) zones. We recommend you select this option, as converting all zones to polyhedral zones eliminates the possibility of hanging nodes and holes in your iso-surfaces or slices. In this case, the number of faces per element is derived from the element-type, and the number of nodes per face is derived from the face-type. The existence of hanging nodes (determined from the existence of a cell-tree and/or face-tree section) adds to the number of faces in the element and the number of nodes in the face that contains the hanging node. Since polygons must have at least 3 nodes, line segment elements will not be converted. When this option is not selected, only FLUENT polytope zones will become Tecplot 360 EX polytope zones. In this case, if hanging nodes are encountered, Tecplot 360 EX will create larger faces, compress connectivity, and expand face neighbors.

• Include Particle Data from .dat - Some FLUENT simulations include the effects of discrete particles, such as sand grains or water droplets, in the .dat file. Select this option to load this particle data along with the flow solution. All particles from a particular injection will be displayed in a single Tecplot 360 EX zone (one zone per injection). If you have chosen to select which zones and variables to load, this option is disabled, but the particle zones and variables will be displayed in the selection lists, allowing you to load them with the flow solution.

Newer versions of FLUENT store the particle data in a separate .xml file. To load this data, use the Load Multiple Case and Data Files mode and simply add any .xml files to the file list.

• Average to Nodes - Selecting this option directs the loader to average FLUENT's cell-centered data to the grid nodes. This can speed up subsequent operations in Tecplot 360 EX, especially slicing. FLUENT stores solution data at cell centers (face centers for boundary zones). By default, the FLUENT data loader loads the data cell-centered as well. However, you have the option to average the data to the nodes using Arithmetic or Laplacian averaging. Arithmetic averaging is faster, but calculates values at hanging nodes (nodes in the center of a cell face or edge) only from those cells where the node is a corner. This can lead to discontinuous contours. Laplacian averaging option takes additional neighboring cells into account, and results in smoother contours when hanging nodes are present. By default, non-grid variables are stored at cell centers, consistent with FLUENT.

• Arithmetic - A simple, fast arithmetic averaging will be performed.

• Laplacian - A more accurate, much slower averaging will be performed that accounts for hanging nodes and cell sizes.

If you chose the Select Zones and Variables to Load option, select only those zones and variables you wish to load from the files Fluent Loader Options dialog.

This dialog has a Zones page and a Variables page. The left-hand list of each page shows, respectively, all zones and variables contained in the files you selected. The right-hand list of each page shows the zones and variables that will be loaded when you select [OK]. Use the [Move], [Move All], [Remove], or [Remove All] buttons to edit the Zones/Variables to Load lists.

4 - 13.1   Macro Commands for the FLUENT loader

The syntax for loading FLUENT data files with the Tecplot macro language is as follows:

Each name/value pair should be in double quotes. Refer to the Scripting Guide for details on working with the Tecplot macro language.