Introduction to GAMBIT

1. Introduction to GAMBIT

2. Agenda Day 1 2:00 Tutorial 3: Edge and Face Meshing Exercises 2:45 Volume Meshing and the Sizing Function 3:45 Tutorial 4: Volume Meshing and Sizing Function Exercises 4:30 Volume Decomposition Examples 5:00 Break for the Day 8:00 Introduction + Demo 9:15 Tutorial 1: Creating and Meshing Basic Geometry 9:45 Creating Geometry in Gambit 10:45 Tutorial 2: Geometry Creation Exercises 12:00 Lunch 1:00 Edge/Face Meshing and Mesh Quality

3. or Agenda Day 2 1:00 Tutorial 7 or 8: Continued 1:30 Tutorial 9: Hex meshing the Flow Probe 3:00 Work on your own Project 1:00 Tutorial 7 or 8: Continued 1:30 G/Turbo + Demo 3:00 Work on your own Project 5:00 Break for the Day 8:00 Tutorial 5: Volume Decomposition Exercises 8:45 Mesh Control through Boundary Layers and Face Vertex Types 9:30 Tutorial 6: Vertex Types 10:30 CAD/CAE Import and Geometry Cleanup + Demo 11:30 Tutorial 7 or 8: Geometry Import Exercise 12:00 Lunch

4. What is GAMBIT? • A single, integrated preprocessor for CFD analysis: • Geometry construction and import • Using ACIS solid modeling capabilities • Using STEP, Parasolid, IGES, etc. import • Cleanup and modification of imported data • Mesh generation for all Fluent solvers (including FIDAP and POLYFLOW) • Structured and Unstructured hexahedral, tetrahedral, pyramid, and prisms. • Mesh quality examination • Boundary zone assignment

5. Operation • General sequence of operations • Initial setup • Solver selection, Mesh size, Defaults, etc. • Geometry Creation (ACIS, STEP, Parasolid, IGES or Mesh import) • Create full geometry • Decompose into mesh-able sections • Meshing • Local meshing: Edge and Boundary layers • Global meshing: Face and/or Volume • Mesh examination • Zone assignment • Continuum and Boundary attachment • Mesh export

6. Files (1) • GAMBIT directory and files • When GAMBIT starts up, it creates a directory called GAMBIT.# • # = the process number • It also creates a “lock” file, ident.lok, in the working directory • ident.lok prevents any user from starting up another session using the same identifier in the same directory. If the code crashes, this file needs to be manually removed. • Three files are created inside this directory • ident.dbs = • jou = • trn = the database. All information will be saved in this file. This file is NOT retrievable upon a crash the journal file. This file is directly accessible from the Run journal form the transcript file. Output from GAMBIT

7. Files (2) • GAMBIT directory and files • GAMBIT permanently saves these files to your working directory as ident.dbs, ident.jou and ident.trn anytime you issue a “Save” option (equivalent to any standard word processor) • Upon Save, earlier versions of ident.dbs and ident.trn will be overwritten, while new commands are appended to the fileident.jou • Upon successful exit of GAMBIT: • The directory GAMBIT.# is removed • The lock-file ident.lok is deleted

8. Before save After save Startup: DEMO • Start gambit with “gambit filename” • NT Users must start Gambit this way from a command prompt. • Example: Start Gambit in directory “projects” • > gambit airfoil

9. Journal Files • Journal File: • Executable list of Gambit commands • Created automatically by Gambit from GUI and TUI. • Can be edited or created externally with text editor. • Journals are small - easy to transfer, e-mail, store • Uses: • Can be parameterized, comments can be added • Easy recovery from a crash or power loss • edit existing commands to create new ones

10. Running 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 modifications • Mark lines in process field to activate for processing. • Editable text field. • Right click text fieldfor more options. • Auto or Step throughactivated process lines.

11. Journal File: Parametric Modeling • Parameters (incl. arrays), control-blocks, do-loops, arithmetic functions, etc., can be used in the Journal File for simplifying parametric studies. Commands are not case sensitive Parameter names begin with $ Comment lines

12. GUI Main Menu bar Operation toolpad Description window Command line Global Control

13. Operation Tool Pads • Boundary Layer • Edge • Face • Volume • Group • Boundary Types Boundary Entity • Continuum Types Continuum Entity Coordinate Systems Sizing Function G/Turbo User-Defined Tools • Vertex • Edge • Face • Volume • Group

14. File Menu (1) • New, Open, Save, SaveAs and Exit • Standard form of database operations • PrintGraphics • Prints graphics to printer or to file • PostScript, BMP, TIF, etc. • RunJournal / Clean Journal • Screen editor/command processor for journal files • Command processing: • Partial or global selection/de-selection • Automatic or stepwise processing • Ability to load the current journal • File browser • Clean Journal removes unnecessary tags, undo’s, etc.

15. File Menu (2) • View File • View of the current output,ident.trn, the transcript file • Ability to view other files as well • Import • ACIS, Parasolid - • IGES, STEP • ICEM Input, Vertex Data • CAD - Pro/E, Optegra Visualizer, I-DEAS FTL • Mesh - mesh and faceted geometry files. • Export • ACIS, Parasolid • IGES, STEP • Mesh - Export your mesh for your Solver. • 2D option guarantees 2D mesh

16. Edit Menu (1) • Edit Title • Title will be included on any printed graphics • EditFile • Ability to launch an editor within GAMBIT • EditParameters • Ability to define, modify and list parameters • parameters: $numeric = 10, • arrays: $array(3,4) = 5 • Parameters and arrays can also be directly defined in the journal file using an editor (preferred option)

17. Edit Menu (2) • Edit Defaults • Modify a large range of defaults that effect: • User Environment • Meshing Characteristics • Geometry • 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.

18. 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

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

20. Global Control (1)

21. Global Control (2) • Scale-to-fit resizes the model to fit the screen • Orient Model - major axes , isometric and: Reverse Previous Journal view • Select Pivot - 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 geometrical entities • Preset configuration of the graphics window 4-view and 4-split Options to return to any single view

22. Global Control (3) • The Window Attributes form • Modify the following attributes (defaults given) • Render Wireframe on ; shaded and hidden off • 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 the use of pick lists

23. Global (4) • Render Model - 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.

24. Forms (1) • Form - components • List box - (picking) • active (yellow) - ready to pick • inactive (white) - click to activate • Radio buttons • mutually exclusive options • Option button • Option menu • Text box • Click-to-focus • Check box • non-mutually exclusive options • Command buttons

25. Forms (2) • Text box • Field for input of data, expressions, parameters • The cursor is blinking if active • To activate - left click in the text box (click-to-focus) • Forms with several text boxes • The order of input is not important • Use “tab” to go to the next text box • Use left click (click-to-focus) to go to any text box

26. Forms (3) • List box • Highlighted in yellow if active • To activate - left click in the list box • Tells you the name of the latest picked item • The item is highlighted in red on the screen • All previously picked items are pink • Individual pick lists for each list box • Forms with several list boxes: • Depending on the form, the order of picking may be important • Use Shift right-click to go to the next list box • Use left click (in the list box) to go to any list box

27. Forms (4) • 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 Un-pick, 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.

28. Mouse Operations (1) • You can toggle between picking with or without “Shift”: • Keep right mouse button down while doing a “left-click” • The cursor now changes to another symbol • Now, Pick/Next/Accept do not need a “Shift” • The Rotation/Translation/Zoom now needs a “Shift”

29. Mouse Operations (2) • The picking philosophy: Left - Middle - Right • Shift-Left: initial pick • Alternative: click and hold, drag diagonally to pick several items at the same time - “window picking” • The latest pick is highlighted in red, previously picked items are highlighted in pink • Shift-Middle: modify pick • The middle pick 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: A Shift-Middle pick on “nothing” is equivalent to “Un-select last pick” • Shift-Right: Apply or go to the next list box