ANSYS CFX-Pre User’s Guide CFX-Pre Modes of Operation When you select File > New Case to create a new simulation, CFX-Pre presents four different modes of operations: Figure 1. The New Cas
e Dialog Box General Mode is the general-purpose mode for defining all types of CFD simulation. This mode uses the general CFX-Pre interface, which is described in Working with the CFX-Pre Interface. Turbomachinery Mode is a customized mode for defining turbomachinery simulations. For details, see Turbomachinery Mode. Quick Setup Mode greatly simplifies the physics setup for a simulation. Quick Setup mode is limited to a single-domain and single-phase problems; more complex physics, such as multiphase, combustion, radiation, advanced turbulence models, etc., are not available. You can, however, use Quick Setup mode to get started, and then add more physics details later. For details, see Quick Setup Mode. Library Template Mode provides a set of library files that are available with templates for specific physical problem definitions. In this mode you can easily define a complex physics problem by loading a template file, importing a mesh, and defining specific problem data. For details, see Library Objects. CFX-Pre File Types This section describes the file types used and produced by CFX-Pre. An overview of the files used throughout ANSYS CFX is available. For details, see CFX File Types in the ANSYS CFX Introduction. Case Files (.cfx) The case file contains the physics data, region definitions, and mesh information for the simulation and is used by CFX-Pre as the 'database' for the simulation setup. The case file is generated when you save a simulation in CFX-Pre. To re-open a simulation, select File > Open Case and pick a case file to open. When you import a mesh into CFX-Pre, it passes through an import filter and is stored as part of the case file. Therefore, once a mesh has been imported, the original mesh file is not required by CFX-Pre. Additional information on importing meshes is available. For details, see Importing Meshes. The case file is a binary file and cannot be directly edited. You can open cases on any supported platform, regardless of the platform on which they were created. Mesh Files There are many types of mesh files that can be imported into CFX-Pre. For details, see Supported Mesh File Types. CFX-Solver Input Files (.def, .mdef) A CFX-Solver input file is created by CFX-Pre. The input file for a single configuration simulation (.def) contains all physics and mesh data; the input file for multi-configuration simulations (.mdef) contains global physics data only (that is, Library and Simulation Control
CFX Command Language specifications). An .mdef input file is supplemented by Configuration Definition (.cfg) files that : Are located in a subdirectory that is named according to the base name of the input file Contain local physics and mesh data. Note Use the–norun command line option (described inCommand-Line Options and Keywords for cfx5solve in ANSYS CFX-Solver Manager User's Guide) to merge global information into the configuration definition files, and produce a CFX-Solver input file (.def) file that can be run by the CFX-Solver. You can load a CFX-Solver input file back into CFX-Pre to recreate a simulation. CFX-Solver input files from previous releases of ANSYS CFX can be loaded into CFX-Pre, although the physics definition may have to be updated for such files. For details, see Physics Errors from Old .def/.res Files. CFX-Solver Results Files (.res, .mres, .trn, .bak) Intermediate and final results files are created by the CFX-Solver: Intermediate results files, which include transient and backup files (.trn and .bak, respectively) are created while running an analysis. Final results files for single and multi-configuration simulations (.res and .mres, respectively) are written at the end of the simulation’s execution. For multi-configuration simulations, a configuration result file (.res) is also created at the end of each configuration’s execution. Each results file contains the following information as of the iteration or time step at which it is written: The physics data (that is, the CFX Command Language specifications) All or a subset of the mesh and solution data. Note CFX-Solver results files can also be used for CFX-Mesh imports. CFX-Solver Backup Results Files (.bak) A backup file (.bak) is created at your request, either by configuring the settings on the Backup tab in Output Control in CFX-Pre, or by choosing to write a backup file while the run is in progress in the CFX-Solver Manager. CFX-Solver Transient Results Files (.trn) A transient results file (.trn) is created at your request, by configuring the settings on the Output Control > Trn Results tab in CFX-Pre. CFX-Solver Error Results Files (.err) An error results file (.err) is created when the CFX-Solver detects a failure and stops executing an analysis. The .err file can be loaded into CFD-Post and treated the same way as a .bak file, but if the CFX-Solver encounters another failure while writing the .err file, it may become corrupted and accurate solutions cannot be guaranteed. Session Files (.pre) Session files are used by CFX-Pre to record CFX Command Language (CCL) commands executed during a session. The commands can be played back at a later date to reproduce the session. These files are in ASCII format and can be edited or written in a text editor. For details, see New Session Command. CCL Files (.ccl)
CFX CCL files are used by CFX-Pre to save CFX Command Language (CCL) statements. CCL files differ from session files in that only a snapshot of the current state is saved to a file. These files are in ASCII format and can be edited or written in a text editor. The CCL statements stored in these files replace or append the existing CCL data, depending on the option chosen. For details, see: ? Import CCL Command ? Append or Replace. CFX-Pre Options When the Options dialog box appears, the CFX-Pre options can be configured under CFX-Pre. ? Record Default Session File When selected, a session file named cfx.xx.pre will be recorded automatically each time CFX-Pre is started (where 'xx' is the next available number). For more information on session files, see Playing a Tutorial Session File. ? Default User Mode can be set to General, Turbo, or Quick Setup. This determines the default mode that CFX-Pre will use when creating a simulation. For details on Turbo mode, see Turbomachinery Mode. For details on Quick Setup mode, see Quick Setup Mode. ? Report CCL Update Summary produces an information window when you load a file that contains CCL from a previous version of CFX-Pre. This window describes the updates that were made to the CCL to make it compatible with the current software release. General Settings made here set the default operation for CFX-Pre; however, you can override these settings for your current simulation by going to the Outline tree view and editing Case Options > General. Auto Generation ? Automatic Default Domain When this option is selected, a domain with the name Default Domain will be created upon importing a mesh. To toggle default domain generation on or off for a session, without affecting the user preference setting, you can right-click the Simulation object in the tree view and select Automatic Default Domain from the shortcut menu. If you manually delete a default domain, the default domain mechanism will be disabled, and a warning message will appear in the physics message window. If you create a domain that uses the same region(s) as the default domain, the latter will be redefined with the remaining locations, or deleted if all the regions are referenced by user-defined domains. If you modify the location of the default domain, the name will change to Default Domain Modified and no additional default domain will be generated. When loading an existing case (cfx file or def file), if there are any mesh volumes that are not assigned to a domain, the default domain generation will be disabled. It can be re-activated as described previously. ? Automatic Default Interfaces
When selected, CFX-Pre will attempt to create domain interfaces when a domain is created or modified. To toggle default interface generation on or off for a session, without affecting the user preference setting, you can right-click the Simulation object in the tree view and select Automatic Default Interfaces from the shortcut menu. Domain interface generation is always deactivated when loading an existing simulation. ? Interface Method When Automatic Default Interfaces has been selected, the Interface Method can be set to one of the following to control how interfaces are automatically generated between domains where regions are found to be connected: o One per Interface Type This method groups as many domains into as few interfaces as possible. o One per Domain Pair An interface is generated for each pair of domains ? Default Boundary can be set to one of the following: o Standard A default boundary condition is created that covers all primitive regions that are not assigned to any boundary condition in the current domain. The default boundary is modified dynamically when other boundary conditions are subsequently added or deleted such that it includes all regions not assigned to any other boundary condition. o One per Relevant Region A default boundary condition on each relevant region not assigned to any boundary condition is created. In this context, ‘relevant' means every composite 2D region, plus any 2D primitive regions that are not referenced by a composite 2D region. If boundary conditions are subsequently deleted, causing some regions to be unassigned, a single default boundary condition will include all such regions. o One per Primitive Region A default boundary condition on each individual 2D primitive region not assigned to any boundary condition is created. If boundary conditions are subsequently deleted, causing some regions to be unassigned, a single default boundary condition will include all such regions. o Disabled Physics ? Disable Physics Validation This option prevents CFX-Pre from issuing messages in the physics message window. For details, see Physics Message Window. ? Enable Beta Features Some beta features are hidden in the user interface. You can select this option to unhide those beta features. When selected, such Beta features will be identified by "(Beta)" in the GUI. ? Automatic Physics Update If this option is selected and you change settings in the simulation definition, CFX-Pre will, for certain settings, respond by changing other settings automatically in an attempt to make problem specification consistent. This incurs an overhead, so for large problems you may wish to disable this feature. ? Show Interface Boundaries in Outline Tree
Shows the interface boundaries in the Outline view. Graphics Style Settings made here set the default operation for CFX-Pre; however, you can override these settings for your current simulation by going to the Outline tree view and editing Case Options > Graphics Style. Object Highlighting Controls how an object that is generated after a change to the setting of this option is highlighted in the viewer. Such highlighting occurs when in picking mode, when selecting a region in a list, or when selecting items in the tree view. Under Type, select one of the following: ? Surface Mesh: Displays the surface mesh for selected regions using lines. ? Face Highlight: Displays the selected regions using faces. ? Wireframe: Traces objects that contain surfaces with green lines. ? Bounding Box: Highlights the selected objects with a green box. Note When you load a case, the highlighting is dictated by the setting that is stored in the case, rather than by the current preferences setting. Background Set Mode to Color or Image. Color Use Color Type to set either a solid color or a gradient of colors; use Color to set the color (and Color2 for gradients). Image Select one of a list of predefined images or a custom image. If selecting a custom image, choose an image file and a type of mapping. Image types that are supported include *.bmp, *.jpg, *.png, and *.ppm. Mapping options are Flat and Spherical. Flat maps are stationary while spherical maps surround the virtual environment and rotate with the objects in the viewer. Custom images have some restrictions: all background images and textures sent to the viewer must be square and must have dimensions that are powers of 2 (for example, 512 x 512 or 1024 x 1024). If the dimensions of your background image is not a power of 2, the viewer sizes the image to be a power of 2 by doing bicubic resampling. To make the background image square, transparent pixels are added to the smaller dimension to make it the same as the larger dimension. The transparent pixels enable you to see the regular viewer background, which gives you control over what fill color your background has. Colors Labels Set the labels to be bright or dark. Legend Text and Turbo Axis Select a color by clicking in the box, or clicking the ellipsis icon. Visibility Axis and Ruler Visibility
Select or clear Axis Visibility or Ruler Visibility to show or hide the axis indicator or ruler in the viewer. Render These settings are used to control the display properties of faces and lines. For details, see Render Options. Mesh Mesh Match Tolerance is used when creating domain interfaces. It is used to determine whether a one-to-one connection can be made at a domain interface. The tolerance is relative to the local mesh length scale; the default value is 0.005 (or 0.5%) of the local edge length on the first side of the interface. A node on the second side must be within this tolerance to a node on the first side for the two to be considered coincident. Mesh Import Options Source Format specifies which type of mesh file is the general default. For details, see Supported Mesh File Types. Source Directory specifies the default directory from which meshes are imported upon selecting the Import Mesh command. It is also possible to set other general options (such as mesh units) and specific advanced options on a per-mesh format basis. Turbo These settings are used in the recognition of turbo regions when importing a mesh using Turbo mode. Labels and Markers The settings under this category control whether labels and boundaries appear in the cases displayed in the 3D Viewer. Settings made here set the default operation for CFX-Pre; however, you can override these settings for your current simulation by going to the Outline tree view and editing Case Options > Labels and Markers. Labels The Show Labels option controls whether any labels are displayed; when enabled, the remaining options control whether particular types of labels are displayed. Boundary Markers When Show Boundary Markers is enabled, the check boxes in that panel control which markers are displayed. The Marker Quantity slider controls the number of markers displayed. Moving the slider to the right increases the number. The Marker Length slider controls the size of the markers displayed. Moving the slider to the right increases the size. Boundary Vectors The Vector Quantity slider controls the number of vectors displayed. Moving the slider to the right increases the number. The Vector Length slider controls the size of the vectors displayed. Moving the slider to the right increases the size. See Boundary Plot Options Tab for a discussion of displaying boundary vectors. Extensions When Include Installed Extension Files is enabled, you have the option of creating a comma-separated list of file to exclude. Customization
The Use Custom Files setting enables the creation of special-purpose interfaces that extend the functionality of CFX-Pre for your environment. Contact your Customer Support representative for more information. The Force generation of rules files an advanced setting used to maintain synchronization of customized RULES files. This option is useful during the development of customized RULES files and is available only when Use Custom Files is enabled. Solve The Definition File Timeout setting controls how long CFX-Pre will wait in seconds while attempting to obtain enough data from the CFX-Solver in order to spawn a CFX-Solver Manager to monitor an existing batch run. This parameter is used when employing the Simulation Control > Start Solver > Run Solver and Monitor command to start the CFX-Solver Manager. See Simulation Control for details on monitoring a running solver batch run.