58:110 Computer-Aided Engineering Spring 2005 Grid Generation in GAMBIT By Xiongbin Liu Department of Mechanical and industrial engineering The University of Iowa February 2005

Introduction GAMBIT: a tool for mesh or grid generation for a CFD solver Two kinds of meshes: (1) Structured mesh (rectangular grid) (2) Unstructured mesh (tetrahedrals (pyramid shape), prisms) Fluent: a CFD solver which can handle both kinds of meshes

Launch Gambit or Fluent 1. mkdir xxx 2. mkdir /var/tmp/name 3. cp ~/problem1/xxx /var/tmp/name 4. cd /var/tmp/name 5. gambit 6. cp xxx ~/problem1 source /usr/ui/class/aux/fluent_setup.csh

GAMBIT graphic user Interface (8 Components) main menu bar Operation Toolpad Form field Global Control Pad Description Windows Transcript Windows Command Box

Main Menu Bar Three Data Files: Filename.jou (Journal, text format, a list of geometry, mesh, zone) Filename.trn (Transcript, text format, a log of messages displayed) Filename.dbs (database, binary format, geometry, mesh)

Mouse operation Left-drag: rotate the model; middle-drag: translate the model; Right-drag: zoom the model in or out, rotate the view of the model about the center; Shift-left-click: highlight the entity in the graphics wiondows and include in the current active pick list.

Global Control Pad

GeometryMeshZonesTools

Basic elements of Geometry Vertex Edge Face Volume (if 3d)

Mesh generation Select mesh edges Spacing (Interval Size, Interval count) Ratio = 1 for Uniform MeshRatio <> 1 For Non Uniform mesh Generate mesh on the face Specify boundary Condition Export mesh data File-Export-Mesh-Export

Practice: Flow passing around half a cylinder (2d) (0,0)