Introduction to GAMBIT

1
Introduction to GAMBIT
2
Agenda Day 1

• 800 Introduction Demo
• 915 Tutorial 1 Creating and
• Meshing Basic Geometry
• 945 Creating Geometry in Gambit
• 1045 Tutorial 2 Geometry Creation
  Exercises
• 1200 Lunch
• 100 Edge/Face Meshing and Mesh Quality

200 Tutorial 3 Edge and Face Meshing
Exercises 245 Volume Meshing and the Sizing
Function 345 Tutorial 4 Volume Meshing
and Sizing Function Exercises 430
Volume Decomposition Examples 500 Break for
the Day
3
Agenda Day 2

• 800 Tutorial 5 Volume Decomposition
  Exercises
• 845 Mesh Control through Boundary Layers
  and Face Vertex Types
• 930 Tutorial 6 Vertex Types
• 1030 CAD/CAE Import and Geometry Cleanup
  Demo
• 1130 Tutorial 7 or 8 Geometry Import
  Exercise
• 1200 Lunch

100 Tutorial 7 or 8 Continued 130
Tutorial 9 Hex meshing the Flow
Probe 300 Work on your own Project 100
Tutorial 7 or 8 Continued 130 G/Turbo
Demo 300 Work on your own Project 500
Break for the Day
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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

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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

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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
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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 file ident.jou
• Upon successful exit of GAMBIT
• The directory GAMBIT. is removed
• The lock-file ident.lok is deleted

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Startup DEMO

• Start gambit with gambit filename
• NT Users must start Gambit this way from a
  command prompt.
• Example Start Gambit in directory projects
• gt gambit airfoil

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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

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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.

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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
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GUI
Main Menu bar
Operation toolpad
Description window
Command line
Global Control
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Operation Tool Pads
Boundary Layer Edge Face Volume Group
Vertex Edge Face Volume Group
Boundary Types Boundary Entity Continuum Types
Continuum Entity
Coordinate Systems Sizing Function G/Turbo User-De
fined Tools
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File Menu (1)

• New, Open, Save, Save As and Exit
• Standard form of database operations
• Print Graphics
• Prints graphics to printer or to file
• PostScript, BMP, TIF, etc.
• Run Journal / 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, undos,
  etc.

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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

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Edit Menu (1)

• Edit Title
• Title will be included on any printed graphics
• Edit File
• Ability to launch an editor within GAMBIT
• Edit Parameters
• 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)

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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.

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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

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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

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Global Control (1)
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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

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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

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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.

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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

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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

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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

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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.

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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
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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