Introduction to GAMBIT

Geometry And Mesh Building Intelligent Toolkit What is GAMBIT? Geometry And Mesh Building Intelligent Toolkit A single, integrated preprocessor for CFD analysis: Geometry construction and import using: ACIS solid modeling capabilities STEP, Parasolid, IGES etc. import (generally requires cleanup) Mesh generation for all FLUENT solvers including FIDAP and POLYFLOW Structured and unstructured hexahedral, tetrahedral, pyramid, and prisms. Mesh quality examination Boundary zone assignment Mesh export

Problem Setup Geometry creation Meshing Examine mesh quality GAMBIT modeling tools Import from CAD/CAE or previously generated mesh file. Clean up and/or decompose into meshable sections Meshing Local meshing – edge, boundary layers and size functions Global meshing – face and/or volume Examine mesh quality Boundary and continuum zone assignment Export the mesh to FLUENT

GAMBIT Startup GAMBIT can be launched using the icon (Windows XP/2000 only). GAMBIT can also be launched from a DOS command prompt or LINUX/UNIX prompt by typing the command gambit sessionID Gambit 2.3 Enter or browse for path to the working directory Enter the session ID or select from previously stored sessions. Startup options

GAMBIT Directory and Files When GAMBIT starts up, it creates a directory called GAMBIT.# # is a randomly assigned, four-digit process number GAMBIT also creates a lock file, sessionID.lok, in the working directory sessionID.lok prevents another user from starting up another session using the same ID in the same directory. If GAMBIT crashes, this file must be removed manually. Three files are created inside the GAMBIT.# directory. The GAMBIT database. All geometry and mesh information is saved in this file. The database is often not retrievable after a crash. sessionID.dbs The journal file. All user instructions are stored in this file. The journal file is directly accessible from the Run Journal form. jou The transcript file. All output from the current GAMBIT session is stored here. trn

GAMBIT Directory and Files GAMBIT permanently saves these files to the working directory as sessionID.dbs, sessionID.jou, and sessionID.trn any time you issue the Save command (equivalent to any standard word processor). The files sessionID.dbs, sessionID.jou, sessionID.trn are overwritten New commands are appended to the journal file, sessionID.jou. Upon successful exit of GAMBIT : The GAMBIT.# directory is removed. The lock file, sessionID.lok, is deleted.

The GAMBIT GUI Main Menu bar Operation Tool Pad Forms Area Transcript Window Global Control Description Window Command line

Operation Tool Pad Vertex Boundary Layer Boundary Types Edge Face Volume Group Boundary Layer Edge Face Volume Groups Boundary Types Continuum Types Coordinate Systems Size Functions G/Turbo Geometry Cleanup Plugin Tools

File Menu New, Open, Save, Save As and Exit Print Graphics Prints graphics to printer or to file PostScript, BMP, TIF, etc. Run Journal / Clean Journal – Journal Utilities Screen editor/command processor for journal files Command processing: Partial or global select/deselect Automatic or stepwise journal file processing Ability to load the current journal file File browser Clean Journal removes unnecessary entries, error commands, undo commands, etc. from the journal file. View File – Opens a generic file viewer View of the current output (the transcript file, ident.trn) Ability to view other files as well

File Menu Import Export ACIS, Parasolid IGES, STEP, Catia V4, Catia V5 (add-on) ICEM Input, Vertex Data CAD Pro/E (STEP or DIRECT (add-on) Optegra Visualizer I-DEAS FTL Mesh - mesh and faceted geometry files. Export IGES, STEP Catia V4 Mesh Export the mesh for your solver. Export 2D mesh option guarantees 2D mesh

Edit Menu Title File – Ability to launch an editor within GAMBIT Title will be included on any printed graphics File – Ability to launch an editor within GAMBIT Parameters – Ability to define, modify and list parameters Defaults Modify a large range of environment variables that affect: User environment Meshing characteristics Geometry manipulation Ability to load, modify and save a new set of defaults in $HOME/GAMBIT.ini which is loaded automatically at startup. Undo/Redo Ten levels of undo/redo (default) Reducing number of levels also reduces memory requirements.

Solver Menu The Solver selection will have an impact on the following input forms: Available meshing algorithms Available element types Continuum types Boundary types Export mesh file Default solver is FLUENT 5/6

Graphical User Interface Transcript Window Output from GAMBIT is printed here as well as in ident.trn. The transcript window can be expanded using the arrow button in the top right corner. Description Window Gives a short description of all global function buttons and screen areas Command Line Input of (non-GUI) commands reset: deletes all mesh and geometry reset mesh: deletes mesh, keeps geometry

Global Control Scale to Fit Pivot anchor control Four Split Four View Light source Labeling Annotation Undo Redo Display Orientation Journal View Modify Label, Visibility, Render, Show/Hide mesh, Silhouette Wireframe, Shaded, Hidden line Color coding by Entity Type or Connectivity Examine Mesh

Global Control – Display Attributes Specify Display Attributes form Modify the following attributes (defaults given) Render Wireframe Mesh Volume OFF Silhouette All ON Label All OFF Visibility All ON Two ways of picking entities All All entities are picked (Default) Pick Individual picking including use of pick lists

Global Control Render Model Modify Light/Label type Color Mode Wireframe Shaded Hidden Modify Light/Label type Change light source orientation and properties Additional information on the entity label Insert arrows and text for graphic presentations Color Mode Color by entity Color by connectivity Undo/Redo Examine Mesh Display different element types by quality, plane cuts, etc.

Forms List Box (picking) Active (yellow) Inactive (white) Radio Button (mutually exclusive) Option Button (activates a menu) Text Box (click to activate/edit) Check Box (non-mutually exclusive) Command Buttons

Forms Text box Field for input of data, expressions, parameters Forms with several text boxes The order of input is not important Use the tab key to go to the next text box Left-Click on any text box to activate. List box The active list box is displayed in yellow Left-Click to activate Tells you the name of the most recently picked item The item is also highlighted in red on the screen All previously picked items are displayed in pink Individual pick lists for each list box Forms with several list boxes: Depending on the task, the order of picking may be important Use Shift + Right-Click to go to the next list box

Forms Pick Lists Open the Pick List by clicking on the arrow The "Available" list is sorted in the order of picking Pick List functionality: Pick or unpick, Selected or All entities by highlight in left column and by clicking on the arrows Highlighted "picked" entities will appear red on the screen edge.32, edge.33 Non-highlighted “picked” entities will appear pink edge.26, edge.28 Right-click in lists area provides additional options Filter can be used to control which objects are picked.

Save view to journal file Mouse Operations Action Left Middle Right Drag x/y Axis Rotation Translate (pan) Zoom / Z-axis Rotation Shift + Click Pick Next Accept / Next Picker Double-Click Previous View Save view to journal file Ctrl + Click Drag zoom Stretch Zoom Click points to grid You can toggle between picking with or without using the Shift key: Press and hold the right mouse button and click the left button. The cursor changes to an eye shape. Now, Pick/Next/Accept do not require the Shift key. The Rotate/Translate/Zoom actions require the Shift key.

Mouse Operations – Selecting Entities Pick a single entity Shift + Left-Click on the entity To pick a face or volume, Shift + Left-Click on one of the bounding edges Pick multiple entities Multiple “single-entity” picks OR Click and hold, drag diagonally to pick several items at the same time Upward diagonal drag will pick everything fully enclosed in the box. Downward diagonal drag will pick anything inside or touching the box. The most recent pick is highlighted in red Previously picked items are highlighted in pink Picking One Face Picking Five Faces This face is not picked

Mouse Operations – Selecting Entities Shift + Middle-Click = Modify Pick The middle mouse button will behave differently depending on the mouse location: Same: Cycle to the next available object within picking tolerance New: Replace last pick with new pick at new location Bad: Shift + Middle-Click on nothing is equivalent to “deselect last pick” Shift + Right-Click = Apply or go to the next list box

GAMBIT Journal Files Executable list of GAMBIT commands Uses: Created automatically by GAMBIT from both the GUI and TUI. Can be created and/or edited manually using a text editor. Journal files are small – easy to transfer, e-mail, etc. Uses: Can be parameterized, comments can be added Easy recovery from a power loss or crash Edit existing commands to create new ones

Running GAMBIT Journal Files Journal files can be processed in two ways: Batch mode (Run) All commands processed without interruption. "read pause" command will force interrupt with resume option appearing. Interactive mode (Edit/Run) Includes text editor for easy modification Mark lines in process field to activate for processing. Editable text field. Right click text field for more options. Auto or Step through activated process lines. File Run Journal

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Global Control Scale-to-fit – zoom in/out to fill the screen Orient Model – major axes , isometric and: Reverse Previous Journal view Select pivot point around which the model rotates, zooms Body center Mouse position Model display attributes Turn on/off visibility, label, silhouette, mesh and hidden line on all or selected geometric entities Preset configuration of the graphics window 4-view and 4-split Options to return to any single view