ANSYS Fluent Meshing User's Guide ANSYS, Inc. Release 15.0 Southpointe November 2013 275 Technology Drive Canonsburg, PA 15317 ANSYS, Inc. is [email protected] certified to ISO 9001:2008. http://www.ansys.com (T) 724-746-3304 (F) 724-514-9494 Copyright and Trademark Information © 2013 SAS IP, Inc. All rights reserved. Unauthorized use, distribution or duplication is prohibited. ANSYS, ANSYS Workbench, Ansoft, AUTODYN, EKM, Engineering Knowledge Manager, CFX, FLUENT, HFSS and any and all ANSYS, Inc. brand, product, service and feature names, logos and slogans are registered trademarks or trademarks of ANSYS, Inc. or its subsidiaries in the United States or other countries. ICEM CFD is a trademark used by ANSYS, Inc. under license. CFX is a trademark of Sony Corporation in Japan. All other brand, product, service and feature names or trademarks are the property of their respective owners. Disclaimer Notice THIS ANSYS SOFTWARE PRODUCT AND PROGRAM DOCUMENTATION INCLUDE TRADE SECRETS AND ARE CONFID- ENTIAL AND PROPRIETARY PRODUCTS OF ANSYS, INC., ITS SUBSIDIARIES, OR LICENSORS.The software products and documentation are furnished by ANSYS, Inc., its subsidiaries, or affiliates under a software license agreement that contains provisions concerning non-disclosure, copying, length and nature of use, compliance with exporting laws, warranties, disclaimers, limitations of liability, and remedies, and other provisions.The software products and documentation may be used, disclosed, transferred, or copied only in accordance with the terms and conditions of that software license agreement. ANSYS, Inc. is certified to ISO 9001:2008. U.S. Government Rights For U.S. Government users, except as specifically granted by the ANSYS, Inc. software license agreement, the use, duplication, or disclosure by the United States Government is subject to restrictions stated in the ANSYS, Inc. software license agreement and FAR 12.212 (for non-DOD licenses). Third-Party Software See the legal information in the product help files for the complete Legal Notice for ANSYS proprietary software and third-party software. If you are unable to access the Legal Notice, please contact ANSYS, Inc. Published in the U.S.A. Table of Contents 1. Using This Manual................................................................................................................................... 1 1.1.The Contents of This Manual............................................................................................................. 1 1.2.Typographical Conventions Used In This Manual................................................................................ 2 1.3. Contacting Technical Support........................................................................................................... 3 2. Introduction to Meshing Mode in ANSYS Fluent.................................................................................... 7 2.1. Meshing Approach........................................................................................................................... 7 2.2. Program Capabilities......................................................................................................................... 7 2.3. ANSYS Fluent Documentation........................................................................................................... 8 2.3.1. Accessing the ANSYS Fluent Documentation............................................................................ 8 2.3.1.1. Accessing the Documentation Files Using the ANSYS Help Viewer.................................... 9 2.3.1.2. Downloading and Installing the PDF Documentation Files................................................ 9 3. Starting and Executing ANSYS Fluent in Meshing Mode...................................................................... 11 3.1. Starting ANSYS Fluent in Meshing Mode......................................................................................... 11 3.1.1. Using Fluent Launcher............................................................................................................ 11 3.1.2. Starting on a Windows System................................................................................................ 13 3.1.3. Starting on a Linux System..................................................................................................... 13 3.1.4. Starting the Dual Process Build............................................................................................... 13 3.1.5. Startup Options ..................................................................................................................... 14 3.2. Parallel Processing in Meshing Mode............................................................................................... 15 3.2.1. Dynamically Spawning Processes Between Fluent Meshing and Fluent Solution Modes........... 16 3.3. Exiting the Program........................................................................................................................ 17 4. Graphical User Interface....................................................................................................................... 19 4.1. GUI Components............................................................................................................................ 19 4.1.1. Menu Bar............................................................................................................................... 20 4.1.2.Toolbars................................................................................................................................. 21 4.1.2.1.The Mode Toolbar.......................................................................................................... 21 4.1.2.2.The Standard Toolbar..................................................................................................... 22 4.1.2.3.The Graphics Toolbars.................................................................................................... 23 4.1.2.4.The Objects Toolbar....................................................................................................... 24 4.1.3.The Navigation Pane............................................................................................................... 24 4.1.4.Task Pages.............................................................................................................................. 25 4.1.5.The Console........................................................................................................................... 25 4.1.6. Dialog Boxes.......................................................................................................................... 26 4.1.6.1. Controls of a Dialog Box................................................................................................. 27 4.1.6.2. Special Dialog Boxes...................................................................................................... 31 4.1.7. Graphics Windows.................................................................................................................. 37 4.1.7.1. Printing the Contents of the Graphics Window (Windows Systems Only)......................... 38 4.1.7.2.The Page Setup Dialog Box............................................................................................ 38 4.2. Customizing the GUI (Linux Systems).............................................................................................. 40 4.3. Using the GUI Help System.............................................................................................................. 41 4.3.1.Task Page and Dialog Box Help............................................................................................... 42 4.3.2. Context-Sensitive Help (Linux Only)........................................................................................ 42 4.3.3. Opening the User’s Guide Table of Contents............................................................................ 42 4.3.4. Opening the Reference Guide................................................................................................. 43 4.3.5. Accessing Printable Manuals.................................................................................................. 44 4.3.6. Help for Text Interface Commands.......................................................................................... 44 4.3.7. Using Help............................................................................................................................. 44 4.3.8. Accessing Online Technical Resources..................................................................................... 44 4.3.9. Obtaining a Listing of Other License Users.............................................................................. 45 4.3.10.Version and Release Information........................................................................................... 45 Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. iii Meshing User's Guide 5.Text User Interface................................................................................................................................ 47 5.1.Text Menu System........................................................................................................................... 47 5.1.1. Command Abbreviation......................................................................................................... 48 5.1.2. Scheme Evaluation................................................................................................................. 49 5.1.3. Aliases ................................................................................................................................... 49 5.2.Text Prompt System........................................................................................................................ 50 5.2.1. Numbers................................................................................................................................ 50 5.2.2. Booleans................................................................................................................................ 51 5.2.3. Strings................................................................................................................................... 51 5.2.4. Symbols................................................................................................................................. 51 5.2.5. Filenames .............................................................................................................................. 52 5.2.6. Lists....................................................................................................................................... 52 5.2.7. Evaluation.............................................................................................................................. 53 5.2.8. Default Value Binding............................................................................................................. 53 5.3. Interrupts ....................................................................................................................................... 53 5.4. System Commands......................................................................................................................... 53 5.4.1. System Commands for LINUX-based Operating Systems......................................................... 53 5.4.2. System Commands for Windows-based Operating Systems..................................................... 54 5.5.Text Menu Input from Character Strings.......................................................................................... 55 5.6. Using the Text Interface Help System............................................................................................... 55 6. Reading and Writing Files..................................................................................................................... 57 6.1. Shortcuts for Reading and Writing Files........................................................................................... 57 6.1.1. Default File Suffixes................................................................................................................ 57 6.1.2. Binary Files............................................................................................................................. 58 6.1.3. Detecting File Format............................................................................................................. 58 6.1.4. Recent File List....................................................................................................................... 58 6.1.5. Reading and Writing Compressed Files................................................................................... 58 6.1.5.1. Reading Compressed Files............................................................................................. 58 6.1.5.2.Writing Compressed Files............................................................................................... 59 6.1.6.Tilde Expansion (LINUX Systems Only).................................................................................... 59 6.1.7. Disabling the Overwrite Confirmation Prompt........................................................................ 59 6.1.8.Toolbar Buttons...................................................................................................................... 59 6.2. Mesh Files....................................................................................................................................... 60 6.2.1. Reading Boundary Mesh Files................................................................................................. 61 6.2.1.1. Reading Multiple Boundary Mesh Files........................................................................... 61 6.2.2. Reading Mesh Files................................................................................................................. 61 6.2.2.1. Reading Multiple Mesh Files .......................................................................................... 61 6.2.2.2. Reading 2D Mesh Files in the 3D Version of ANSYS Fluent............................................... 62 6.2.3. Reading Faceted Geometry Files from ANSYS Workbench in ANSYS Fluent.............................. 62 6.2.4. Appending Mesh Files............................................................................................................ 62 6.2.5.Writing Mesh Files.................................................................................................................. 63 6.2.6.Writing Boundary Mesh Files.................................................................................................. 63 6.3. Case Files........................................................................................................................................ 63 6.3.1. Reading Case Files.................................................................................................................. 64 6.3.1.1. Reading Multiple Case Files ........................................................................................... 64 6.3.2.Writing Case Files................................................................................................................... 64 6.4. Size-Field Files ................................................................................................................................ 65 6.4.1. Reading Size-Field Files.......................................................................................................... 65 6.4.2.Writing Size-Field Files............................................................................................................ 66 6.5. Reading Scheme Source Files.......................................................................................................... 66 6.6. Creating and Reading Journal Files.................................................................................................. 66 6.7. Creating Transcript Files.................................................................................................................. 68 Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information iv of ANSYS, Inc. and its subsidiaries and affiliates. Meshing User's Guide 6.8. Domain Files................................................................................................................................... 69 6.9. Importing Files ............................................................................................................................... 69 6.9.1. ANSYS Prep7 Files.................................................................................................................. 70 6.9.2. CGNS Files.............................................................................................................................. 70 6.9.3. Importing FIDAP Neutral Mesh Files........................................................................................ 70 6.9.4. Importing GAMBIT Neutral Mesh Files..................................................................................... 71 6.9.5. HYPERMESH ASCII Files........................................................................................................... 71 6.9.6. I-deas Universal Files.............................................................................................................. 71 6.9.7. NASTRAN Files....................................................................................................................... 72 6.9.8. PATRAN Neutral Files.............................................................................................................. 72 6.9.9. Importing CAD Files............................................................................................................... 72 6.9.9.1.Text Commands for Importing CAD Files........................................................................ 76 6.9.10. Grid Import Filter Options..................................................................................................... 78 6.9.10.1.Text Commands for Setting Filter Options..................................................................... 78 6.10. Exporting STL Files........................................................................................................................ 78 6.11. Saving Picture Files....................................................................................................................... 78 6.11.1. Using the Save Picture Dialog Box......................................................................................... 78 6.11.2.Text Interface for Saving Picture Files.................................................................................... 82 6.12.The .tgrid File................................................................................................................................ 83 6.13. Exiting the Meshing Mode............................................................................................................ 84 7. Size Functions....................................................................................................................................... 85 7.1.Types of Size Functions................................................................................................................... 85 7.1.1. Curvature Size Function.......................................................................................................... 86 7.1.2. Proximity Size Function.......................................................................................................... 87 7.1.3. Meshed Size Function............................................................................................................ 90 7.1.4. Hard Size Function................................................................................................................. 91 7.1.5. Soft Size Function.................................................................................................................. 91 7.1.6. Body of Influence Size Function.............................................................................................. 92 7.2. Defining Size Functions................................................................................................................... 93 7.2.1. Creating Default Size Functions.............................................................................................. 94 7.2.2. Computing the Size Field........................................................................................................ 95 7.2.2.1. Size Field Files................................................................................................................ 95 7.2.2.2. Using Size Field Filters.................................................................................................... 95 7.2.2.3.Visualizing Sizes............................................................................................................. 96 7.3. Using Size Functions/Size Field........................................................................................................ 97 7.4.Text Commands for Size Functions.................................................................................................. 98 8. Meshing Objects and Material Points................................................................................................. 103 8.1. Objects......................................................................................................................................... 103 8.1.1. Object Attributes.................................................................................................................. 103 8.1.1.1. Approaches For Creating Objects................................................................................. 105 8.1.2. Object Based Meshing.......................................................................................................... 106 8.1.3. Using the Manage Objects Dialog Box.................................................................................. 107 8.1.3.1. Defining Objects.......................................................................................................... 107 8.1.3.2. Creating Multiple Objects............................................................................................ 108 8.1.3.3. Object Manipulation Operations.................................................................................. 108 8.1.3.4. Object Transformation Operations............................................................................... 109 8.1.3.5. Automatic Alignment of Objects.................................................................................. 110 8.1.4.Text Commands for Objects.................................................................................................. 110 8.2. Material Points.............................................................................................................................. 114 8.2.1. Using the Material Point Dialog Box...................................................................................... 117 8.2.2. Using Text Commands.......................................................................................................... 117 9. Manipulating the Boundary Mesh...................................................................................................... 119 Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. v Meshing User's Guide 9.1. Manipulating Boundary Nodes...................................................................................................... 119 9.1.1. Free and Isolated Nodes....................................................................................................... 119 9.1.2.Text Commands for Manipulating Boundary Nodes............................................................... 120 9.2. Intersecting Boundary Zones........................................................................................................ 121 9.2.1. Intersecting Zones................................................................................................................ 121 9.2.2. Joining Zones....................................................................................................................... 122 9.2.3. Stitching Zones.................................................................................................................... 123 9.2.4. Using the Intersect Boundary Zones Dialog Box.................................................................... 125 9.2.5.Text Commands for Boundary Intersection............................................................................ 126 9.3. Modifying the Boundary Mesh...................................................................................................... 128 9.3.1. Using the Modify Boundary Dialog Box................................................................................. 128 9.3.2. Operations Performed: Modify Boundary Dialog Box............................................................. 128 9.3.3. Locally Remeshing a Boundary Zone or Faces....................................................................... 135 9.3.4.Text Commands for Boundary Modification.......................................................................... 135 9.4. Improving Boundary Surfaces....................................................................................................... 138 9.4.1. Improving the Boundary Surface Quality.............................................................................. 138 9.4.2. Smoothing the Boundary Surface......................................................................................... 138 9.4.3. Swapping Face Edges........................................................................................................... 138 9.4.4.Text Commands for Improving Boundary Surfaces................................................................ 139 9.5. Refining the Boundary Mesh......................................................................................................... 139 9.5.1. Procedure for Refining Boundary Zone(s).............................................................................. 139 9.5.2.Text Commands for Boundary Zone Refinement................................................................... 141 9.6. Creating and Modifying Features................................................................................................... 142 9.6.1. Creating Edge Loops............................................................................................................ 142 9.6.2. Modifying Edge Loops.......................................................................................................... 145 9.6.3. Using the Feature Modify Dialog Box.................................................................................... 146 9.6.4.Text Commands for Creating and Modifying Features............................................................ 148 9.7. Remeshing Boundary Zones.......................................................................................................... 149 9.7.1. Creating Edge Loops............................................................................................................ 150 9.7.2. Modifying Edge Loops.......................................................................................................... 150 9.7.3. Remeshing Boundary Face Zones......................................................................................... 150 9.7.4. Using the Surface Retriangulation Dialog Box....................................................................... 151 9.7.5.Text Commands for Remeshing............................................................................................ 152 9.8. Faceted Stitching of Boundary Zones............................................................................................ 154 9.9.Triangulating Boundary Zones....................................................................................................... 155 9.10. Separating Boundary Zones........................................................................................................ 155 9.10.1. Methods for Separating Face Zones.................................................................................... 155 9.10.2.Text Commands for Separating Face Zones......................................................................... 158 9.11. Projecting Boundary Zones......................................................................................................... 159 9.11.1.Text Commands for Projecting Boundary Zones.................................................................. 159 9.12. Creating Groups.......................................................................................................................... 159 9.12.1.Text Commands for User-Defined Groups............................................................................ 160 9.13. Manipulating Boundary Zones.................................................................................................... 161 9.13.1.Text Commands for Manipulating Boundary Zones............................................................. 161 9.14. Manipulating Boundary Conditions............................................................................................. 162 9.14.1.Text Commands for Manipulating Boundary Conditions...................................................... 163 9.15. Creating Surfaces........................................................................................................................ 163 9.15.1. Creating a Bounding Box.................................................................................................... 163 9.15.1.1. Using the Bounding Box Dialog Box........................................................................... 163 9.15.2. Creating a Planar Surface Mesh........................................................................................... 164 9.15.2.1. Using the Plane Surface Dialog Box............................................................................ 165 9.15.3. Creating a Cylinder/Frustum............................................................................................... 166 Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information vi of ANSYS, Inc. and its subsidiaries and affiliates. Meshing User's Guide 9.15.3.1. Using the Cylinder Dialog Box.................................................................................... 168 9.15.4. Creating a Swept Surface.................................................................................................... 169 9.15.4.1. Using the Swept Surface Dialog Box........................................................................... 169 9.15.5. Creating a Revolved Surface............................................................................................... 170 9.15.5.1. Using the Revolved Surface Dialog Box....................................................................... 170 9.15.6. Creating Periodic Boundaries.............................................................................................. 171 9.15.7.Text Commands for Creating Surfaces................................................................................. 172 9.16. Additional Boundary Mesh Text Commands................................................................................. 172 10.Wrapping Boundaries....................................................................................................................... 177 10.1.The Wrapping Process................................................................................................................. 178 10.2. Examining and Repairing the Input Geometry............................................................................. 179 10.3. Initializing the Cartesian Grid....................................................................................................... 182 10.4. Examining the Cartesian Grid for Leakages.................................................................................. 186 10.4.1. Automatic Leak Detection.................................................................................................. 187 10.4.2. Manual Leak Detection....................................................................................................... 188 10.5. Extracting the Wrapper Surface................................................................................................... 191 10.6. Checking the Quality of the Wrapper Surface............................................................................... 194 10.7. Post Wrapping Improvement Operations..................................................................................... 195 10.7.1. Coarsening Options............................................................................................................ 195 10.7.2. Post Wrap Options.............................................................................................................. 196 10.7.3. Zone Options..................................................................................................................... 202 10.7.4. Expert Options................................................................................................................... 204 10.8.Text Commands for the Wrapper................................................................................................. 206 11. Creating a Mesh................................................................................................................................. 211 11.1. Choosing the Meshing Strategy................................................................................................... 211 11.1.1. Boundary Mesh Containing Only Triangular Faces............................................................... 212 11.1.2. Mixed Boundary Mesh........................................................................................................ 213 11.1.3. Hexcore Mesh .................................................................................................................... 214 11.1.4. CutCell Mesh...................................................................................................................... 214 11.1.5. Additional Meshing Tasks................................................................................................... 215 11.1.6. Inserting Isolated Nodes into a Tet Mesh............................................................................. 217 11.2. Using the Auto Mesh Dialog Box.................................................................................................. 219 11.2.1.Text Commands for Auto Mesh........................................................................................... 220 11.3. Generating Pyramids................................................................................................................... 220 11.3.1. Creating Pyramids.............................................................................................................. 221 11.3.2. Zones Created During Pyramid Generation......................................................................... 222 11.3.3.Text Commands for Generating Pyramids............................................................................ 223 11.3.4. Pyramid Meshing Problems................................................................................................ 223 11.4. Creating a Non-Conformal Interface............................................................................................ 225 11.4.1. Separating the Non-Conformal Interface Between Cell Zones.............................................. 225 11.4.2.Text Commands for Creating a Non-Conformal Interface..................................................... 226 11.5. Creating a Heat Exchanger Zone.................................................................................................. 226 11.6. Parallel Meshing.......................................................................................................................... 227 11.6.1.Text Commands ................................................................................................................. 228 12. Generating Prisms............................................................................................................................. 229 12.1. Overview.................................................................................................................................... 229 12.2. Procedure for Generating Prisms................................................................................................. 230 12.3. Prism Meshing Options............................................................................................................... 232 12.3.1. Growing Prisms Simultaneously from Multiple Zones.......................................................... 232 12.3.2. Growing Prisms on a Two-Sided Wall................................................................................... 234 12.3.3. Detecting Proximity and Collision....................................................................................... 235 12.3.4. Ignoring Invalid Normals.................................................................................................... 238 Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. vii Meshing User's Guide 12.3.5. Splitting Prism Layers......................................................................................................... 238 12.3.6. Preserving Orthogonality ................................................................................................... 239 12.4. Zones Created During Prism Generation...................................................................................... 239 12.5.The Prism Generation Process...................................................................................................... 240 12.6. Using Adjacent Zones as the Sides of Prisms................................................................................ 241 12.7. Direction Vectors......................................................................................................................... 244 12.8. Offset Distances.......................................................................................................................... 247 12.9. Improving Prism Quality.............................................................................................................. 249 12.9.1. Edge Swapping and Smoothing.......................................................................................... 249 12.9.2. Node Smoothing................................................................................................................ 250 12.9.3. Improving the Prism Quality............................................................................................... 250 12.9.4. Removing Poor Quality Cells............................................................................................... 251 12.9.5. Improving Warp ................................................................................................................. 252 12.10.Text Commands for Generating Prisms....................................................................................... 252 12.11. Prism Meshing Problems........................................................................................................... 261 13. Generating Thin Volume Mesh.......................................................................................................... 265 13.1. Overview.................................................................................................................................... 265 13.2. Procedure for Generating a Thin Volume Mesh............................................................................. 265 13.3.Text Command for Generating Thin Volume Mesh........................................................................ 266 14. Generating Tetrahedral Meshes........................................................................................................ 267 14.1. Automatically Creating a Tetrahedral Mesh.................................................................................. 267 14.1.1. Automatic Meshing Procedure for Tetrahedral Meshes........................................................ 267 14.1.2. Using the Auto Mesh Tool................................................................................................... 269 14.1.3. Automatic Meshing of Multiple Cell Zones.......................................................................... 269 14.1.4. Automatic Meshing for Hybrid Meshes................................................................................ 270 14.1.5. Further Mesh Improvements............................................................................................... 270 14.2. Manually Creating a Tetrahedral Mesh......................................................................................... 271 14.2.1. Manual Meshing Procedure for Tetrahedral Meshes............................................................. 271 14.3. Initializing the Tetrahedral Mesh.................................................................................................. 274 14.3.1. Using the Tet Dialog Box..................................................................................................... 274 14.3.2.Text Commands for Initializing the Mesh............................................................................. 275 14.4. Refining the Tetrahedral Mesh..................................................................................................... 276 14.4.1. Using Local Refinement Regions......................................................................................... 277 14.4.2. Using the Tet Dialog Box..................................................................................................... 278 14.4.3.Text Commands for Setting Refinement Controls................................................................. 279 14.5. Additional Text Commands for Tetrahedral Mesh Generation....................................................... 281 14.6. Common Tetrahedral Meshing Problems..................................................................................... 282 15. Generating the Hexcore Mesh........................................................................................................... 285 15.1. Hexcore Meshing Procedure........................................................................................................ 285 15.2. Using the Hexcore Dialog Box...................................................................................................... 286 15.3. Controlling Hexcore Parameters.................................................................................................. 287 15.3.1. Defining Hexcore Extents................................................................................................... 287 15.3.2. Hexcore to Selected Boundaries.......................................................................................... 288 15.3.3. Only Hexcore...................................................................................................................... 289 15.3.4. Maximum Cell Length......................................................................................................... 290 15.3.5. Buffer Layers ...................................................................................................................... 291 15.3.6. Peel Layers......................................................................................................................... 291 15.3.7. Local Refinement Regions.................................................................................................. 292 15.4.Text Commands for Hexcore Meshing.......................................................................................... 292 16. Generating the CutCell Mesh............................................................................................................ 295 16.1.The CutCell Meshing Process....................................................................................................... 295 16.2. Using the CutCell Dialog Box....................................................................................................... 300 Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information viii of ANSYS, Inc. and its subsidiaries and affiliates. Meshing User's Guide 16.2.1. Handling Zero-Thickness Walls............................................................................................ 301 16.2.2. Handling Overlapping Surfaces.......................................................................................... 302 16.2.3. Resolving Thin Regions....................................................................................................... 303 16.3. Improving the CutCell Mesh........................................................................................................ 304 16.4. Post CutCell Mesh Generation Cleanup........................................................................................ 305 16.5. Generating Prisms for the CutCell Mesh....................................................................................... 305 16.6.The Cut-Tet Workflow.................................................................................................................. 309 16.7.Text Commands for CutCell Meshing........................................................................................... 311 17. Object-Based Meshing...................................................................................................................... 317 17.1. Object-Based Meshing Workflow................................................................................................. 317 17.1.1. Using the Mesh Generation Task Page................................................................................. 318 17.2. Preparing the Geometry.............................................................................................................. 319 17.2.1. Using a Bounding Box........................................................................................................ 320 17.2.2. Closing Annular Gaps in the Geometry................................................................................ 320 17.2.3. Creating Capping Surfaces.................................................................................................. 320 17.2.4. Defining Material Points..................................................................................................... 322 17.2.5. Defining Size Functions...................................................................................................... 323 17.2.6. Using User-Defined Groups................................................................................................ 323 17.3. Defining Objects......................................................................................................................... 323 17.4. Diagnostics................................................................................................................................. 323 17.4.1. Geometry Issues................................................................................................................. 324 17.4.2. Face Connectivity Issues..................................................................................................... 324 17.4.3. Quality Checking................................................................................................................ 325 17.5. Fixing Holes in Objects................................................................................................................ 325 17.6.Wrapping Objects....................................................................................................................... 327 17.6.1. Object Wrapping Options................................................................................................... 329 17.6.1.1.Wrapping Selected Objects........................................................................................ 329 17.6.1.2. Creating a New Wrap Object...................................................................................... 329 17.6.1.3. Resolving Thin Regions During Object Wrapping........................................................ 331 17.6.2. Repairing Wrap Objects...................................................................................................... 331 17.6.2.1. Detecting Holes in the Wrap Object............................................................................ 331 17.6.2.2. Removing Gaps Between Wrap Objects...................................................................... 331 17.6.2.3. Removing Thickness in Wrap Objects......................................................................... 333 17.6.2.4. Improving Feature Capture For Wrap Objects............................................................. 335 17.7. Sewing Objects........................................................................................................................... 335 17.7.1. Improving Wrap Objects..................................................................................................... 337 17.7.2. Resolving Thin Regions....................................................................................................... 337 17.7.3. Processing Slits................................................................................................................... 337 17.8. Improving the Mesh Objects....................................................................................................... 338 17.8.1. Removing Voids ................................................................................................................. 338 17.8.2. Improving Feature Capture For Mesh Objects...................................................................... 338 17.9. Build Topology............................................................................................................................ 338 17.9.1.Text commands for Build Topology..................................................................................... 341 17.10. Generating the Volume Mesh Based on Mesh Objects................................................................ 342 17.11.Text Commands for Object Based Meshing................................................................................ 343 18. Improving the Mesh.......................................................................................................................... 347 18.1. Smoothing Nodes....................................................................................................................... 347 18.1.1. Laplace Smoothing ............................................................................................................ 347 18.1.2.Variational Smoothing........................................................................................................ 348 18.1.3. Skewness-Based Smoothing............................................................................................... 348 18.1.4.Text Commands for Smoothing........................................................................................... 348 18.2. Swapping ................................................................................................................................... 349 Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. ix Meshing User's Guide 18.2.1.Text Commands for Swapping............................................................................................ 350 18.3. Improving the Mesh.................................................................................................................... 350 18.4. Removing Slivers from a Tetrahedral Mesh................................................................................... 350 18.4.1. Automatic Sliver Removal................................................................................................... 351 18.4.2. Removing Slivers Manually................................................................................................. 351 18.4.3.Text Commands for Sliver Removal..................................................................................... 352 18.5. Modifying Cells........................................................................................................................... 353 18.5.1. Using the Modify Cells Dialog Box....................................................................................... 353 18.5.2.Text Commands for Modifying Cell Zones............................................................................ 355 18.6. Moving Nodes ............................................................................................................................ 356 18.6.1. Automatic Correction......................................................................................................... 356 18.6.2. Semi-Automatic Correction ................................................................................................ 357 18.6.3. Repairing Negative Volume Cells......................................................................................... 358 18.6.4.Text Commands for Moving Nodes..................................................................................... 358 18.7. Cavity Remeshing....................................................................................................................... 358 18.7.1.Tetrahedral Cavity Remeshing............................................................................................. 359 18.7.2. Hexcore Cavity Remeshing................................................................................................. 361 18.7.3.Text Commands for Cavity Remeshing................................................................................ 363 18.8. Manipulating Cell Zones.............................................................................................................. 364 18.8.1. Active Zones and Cell Types................................................................................................ 364 18.8.2. Copying and Moving Cell Zones.......................................................................................... 364 18.8.3.Text Commands for Manipulating Cell Zones....................................................................... 365 18.9. Manipulating Cell Zone Conditions.............................................................................................. 368 18.9.1.Text Commands for Manipulating Cell Zone Conditions....................................................... 368 18.10. Using Domains to Group and Mesh Boundary Faces................................................................... 368 18.10.1. Using Domains................................................................................................................. 368 18.10.2. Defining Domains ............................................................................................................ 369 18.10.3.Text Commands for Domains............................................................................................ 369 18.11. Checking the Mesh................................................................................................................... 370 18.12. Checking the Mesh Quality........................................................................................................ 371 18.13. Clearing the Mesh..................................................................................................................... 371 19. Examining the Mesh.......................................................................................................................... 373 19.1. Displaying the Grid..................................................................................................................... 373 19.1.1. Generating the Grid Display Using the Display Grid Dialog Box............................................ 374 19.1.2. Grid Display Options........................................................................................................... 374 19.1.3.Text Commands for Displaying the Grid.............................................................................. 375 19.1.4.Text Commands for Grid Colors........................................................................................... 378 19.1.5.Text Commands for Style Attributes.................................................................................... 378 19.1.6. Displaying Objects ............................................................................................................. 379 19.1.6.1.Text Commands for Displaying Objects...................................................................... 379 19.2. Checking Face Distribution.......................................................................................................... 380 19.2.1.Text Commands for Face Distribution.................................................................................. 380 19.3. Checking Cell Distribution........................................................................................................... 380 19.3.1.Text Commands for Cell Distribution................................................................................... 380 19.4. Modifying the Attributes of the Plot Axes..................................................................................... 381 19.4.1.Text Commands for Modifying Axes Attributes.................................................................... 381 19.5. Controlling Display Options......................................................................................................... 381 19.5.1. Modifying the Display Options............................................................................................ 382 19.5.2.Text Commands for Controlling Display Options.................................................................. 383 19.6. Modifying the View..................................................................................................................... 386 19.6.1.Text Commands for Modifying the View.............................................................................. 386 19.7. Adding Lights............................................................................................................................. 387 Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information x of ANSYS, Inc. and its subsidiaries and affiliates.