ANSYS Meshing User's Guide Release 13.0ANSYS, Inc. November 2010Southpointe 275 Technology Drive Canonsburg, PA 15317 ANSYS, Inc. is certified to ISO 9001:2008. ansysinfo@ansys.com http://www.ansys.com (T) 724-746-3304 (F) 724-514-9494 Copyright and Trademark Information © 2010 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. 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Table of Contents Capabilities in Workbench 1 Meshing Overview 1 Meshing Implementation in ANSYS Workbench 3 Types of Meshing 4 Meshing by Algorithm 4 Meshing by Element Shape 6 Conformal Meshing Between Parts 7 Usage in Workbench 11 Basic Meshing Application Workflows 11 Overview of the Meshing Process in ANSYS Workbench 11 Overview of the Meshing Process for CFD/Fluids Analyses 12 Combining CFD/Fluids Meshing and Structural Meshing 13 Strategies for CFD/Fluids Meshing in ANSYS Workbench 15 Accessing Meshing Functionality 17 Overview of the Meshing Application Interface 18 Determination of Physics, Analysis, and Solver Settings 19 Working with Legacy Mesh Data 20 Exporting Meshes or Faceted Geometry 22 Mesh Application File Export 23 FLUENT Mesh Export 23 Classes of Zone Types in ANSYS FLUENT 25 Standard Naming Conventions for Naming Named Selections 27 Zone Type Assignment 28 Example of ANSYS FLUENT Workflow in ANSYS Workbench 32 POLYFLOW Export 35 CGNS Export 36 ICEM CFD Export 36 Exporting Faceted Geometry to TGrid 44 Extended ANSYS ICEM CFD Meshing 47 Writing ANSYS ICEM CFD Files 47 Rules for Interactive Editing 49 Limitations of ANSYS ICEM CFD Interactive 49 Working with Meshing Application Parameters 49 ANSYS Workbench and Mechanical APDL Application Meshing Differences 50 Mesh Controls Overview 53 Global and Local Mesh Controls 53 Understanding the Influence of the Advanced Size Function 53 Global Mesh Controls 57 Defaults Group 57 Physics Preference 57 Solver Preference 59 Relevance 59 Sizing Group 59 Use Advanced Size Function 59 Curvature Size Function 61 Proximity Size Function 61 Fixed Size Function 62 Specifying Size Function Options 62 Curvature Normal Angle 63 Proximity Accuracy 63 iii Release 13.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. Num Cells Across Gap 63 Proximity Size Function Sources 64 Min Size 64 Max Face Size 64 Max Size 65 Growth Rate 65 Relevance Center 65 Element Size 66 Initial Size Seed 66 Smoothing 66 Transition 67 Span Angle Center 67 Minimum Edge Length 67 Inflation Group 67 Use Automatic Inflation 69 None 69 Program Controlled 69 All Faces in Chosen Named Selection 70 Inflation Option 71 Transition Ratio 72 Maximum Layers 73 Growth Rate 73 Number of Layers 73 Maximum Thickness 73 First Layer Height 74 First Aspect Ratio 74 Aspect Ratio (Base/Height) 74 Inflation Algorithm 74 View Advanced Options 77 Collision Avoidance 77 Fix First Layer 81 Gap Factor 81 Maximum Height over Base 81 Growth Rate Type 82 Maximum Angle 82 Fillet Ratio 83 Use Post Smoothing 84 Smoothing Iterations 84 CutCellMeshing Group 84 Active 84 Feature Capture 84 Tessellation Refinement 85 Advanced Group 85 Shape Checking 85 Element Midside Nodes 87 Straight Sided Elements 88 Number of Retries 88 Extra Retries For Assembly 89 Rigid Body Behavior 89 Mesh Morphing 89 Defeaturing Group 90 Pinch 90 Release 13.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. iv ANSYS Meshing User's Guide Pinch Control Automation Overview 93 How to Define Pinch Control Automation 96 How to Define or Change Pinch Controls Manually 97 Usage Information for Pinch Controls 97 Loop Removal 99 Automatic Mesh Based Defeaturing 99 Statistics Group 101 Nodes 101 Elements 101 Mesh Metric 101 Element Quality 106 Aspect Ratio Calculation for Triangles 106 Aspect Ratio Calculation for Quadrilaterals 107 Jacobian Ratio 108 Warping Factor 110 Parallel Deviation 113 Maximum Corner Angle 114 Skewness 114 Orthogonal Quality 117 Local Mesh Controls 121 Method Control 122 Method Controls and Element Midside Nodes Settings 122 Setting the Method Control for Solid Bodies 125 Automatic Method Control 125 Tetrahedrons Method Control 125 Patch Conforming Algorithm for Tetrahedrons Method Control 125 Patch Independent Algorithm for Tetrahedrons Method Control 126 Hex Dominant Method Control 146 Sweep Method Control 147 MultiZone Method Control 150 Setting the Method Control for Surface Bodies 155 Quadrilateral Dominant Method Control 155 Triangles Method Control 155 Uniform Quad/Tri Method Control 156 Uniform Quad Method Control 157 Sizing Control 157 Using the Local Sizing Control 158 Defining Local Mesh Sizing on a Body 158 Defining Local Mesh Sizing on a Face 159 Defining Local Mesh Sizing on an Edge 159 Defining Local Mesh Sizing on a Vertex 159 Descriptions of Local Sizing Control Options 160 Notes on Element Sizing 164 Contact Sizing Control 166 Refinement Control 167 Mapped Face Meshing Control 168 Setting Basic Mapped Face Meshing Controls 168 Understanding Advanced Mapped Face Meshing Controls 169 Restrictions Related to Vertex Types 170 Restrictions Related to Edge Mesh Intervals 171 Selecting Faces and Vertices 171 Effect of Vertex Type on Face Meshes 173 v Release 13.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. ANSYS Meshing User's Guide Setting Advanced Mapped Face Meshing Controls 174 Notes on the Mapped Face Meshing Control 175 Match Control 177 Cyclic Match Control 178 Arbitrary Match Control 179 Pinch Control 181 Defining Pinch Controls Locally 181 Changing Pinch Controls Locally 183 Inflation Control 185 Gap Tool 188 Options 191 Accessing the Options Dialog Box 191 Common Settings Option on the Options Dialog Box 191 Meshing Options on the Options Dialog Box 192 Specialized Meshing 195 Mesh Sweeping 195 Thin Model Sweeping 199 MultiZone Meshing 212 MultiZone Overview 213 MultiZone Support for Inflation 213 MultiZone Support for Defined Edge and Face Sizings 214 MultiZone Algorithms 214 Using MultiZone 216 MultiZone Source Face Selection Tips 219 MultiZone Source Face Imprinting Guidelines 219 Internal Loops 220 Boundary Loops 220 Multiple Internal Loops 221 Multiple Connected Internal Loops 222 Internal Cutout Loops 223 Parallel Loops 225 Intersecting Loops 226 Using Virtual Topology to Handle Fillets in MultiZone Problems 227 MultiZone Limitations and Hints 227 CutCell Meshing 228 The CutCell Meshing Process 228 The CutCell Meshing Workflow 231 Direct Meshing 239 Inflation Controls 244 Mesh Refinement 250 Mixed Order Meshing 250 Air Gap Meshing 250 Contact Meshing 251 Winding Body Meshing 251 Wire Body Meshing 251 Pyramid Transitions 251 Match Meshing and the Symmetry Folder 251 Rigid Body Meshing 251 Thin Solid Meshing 254 CAD Instance Meshing 254 Meshing and Hard Entities 256 Baffle Meshing 257 Release 13.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. vi ANSYS Meshing User's Guide Mesh Control Interaction Tables 261 Interactions Between Mesh Methods 261 Interactions Between Mesh Methods and Mesh Controls 263 Miscellaneous Tools 267 Generation of Contact Elements 267 Renaming Mesh Control Tool 267 Mesh Numbering 268 Mesh Connection 268 Ease of Use Features 269 Updating the Mesh Cell State 269 Generating Mesh 270 Previewing Surface Mesh 271 Exporting a Previewed Surface Mesh in FLUENT Format 273 Previewing Source and Target Mesh 273 Previewing Inflation 274 Exporting a Previewed Inflation Mesh in FLUENT Format 275 Showing Program Controlled Inflation Surfaces 275 Showing Sweepable Bodies 276 Showing Problematic Geometry 276 Showing Geometry in Overlapping Named Selections 276 Showing Removable Loops 277 Inspecting Large Meshes Using Named Selections 277 Clearing Generated Data 277 Showing Missing Tessellations 278 Showing Mappable Faces 279 Virtual Topology 281 Introduction 281 Creating Virtual Cells 281 Creating Virtual Split Edges 285 Named Selections and Regions for CFX 291 Troubleshooting 293 Tutorials 299 Tutorial 1: Can Combustor 299 Geometry Import 300 Mesh Generation 302 Tutorial 2: Single Body Inflation 307 Tutorial Setup 308 Mesh Generation 308 Tutorial 3: Mesh Controls and Methods 318 Tutorial Setup 318 Mesh Generation 319 Index 337 vii Release 13.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. ANSYS Meshing User's Guide Release 13.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. viii Capabilities in Workbench The following topics are discussed in this section. Meshing Overview Meshing Implementation in ANSYS Workbench Types of Meshing Conformal Meshing Between Parts Meshing Overview Philosophy The goal of meshing in ANSYS Workbench is to provide robust, easy to use meshing tools that will simplify the mesh generation process. These tools have the benefit of being highly automated along with having a moderate to high degree of user control. Physics Based Meshing When the Meshing application is launched (that is, edited) from the ANSYS Workbench Project Schematic, the physics preference will be set based on the type of system being edited. For analysis systems, the appro- priate physics is used. For a Mechanical Model system, the Mechanical physics preference is used. For a Mesh system, the physics preference defined in Tools> Options> Meshing> Default Physics Preference is used. Upon startup of the Meshing application from a Mesh system, you will see the Meshing Options panel shown below. This panel allows you to quickly and easily set your meshing preferences based on the physics you are preparing to solve. If you remove the panel after startup, you can display the panel again by clicking the Options button from the Mesh toolbar. 1 Release 13.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. Physics Preference The first option the panel allows you to set is your Physics Preference. This corresponds to the Physics Preference value in the Details View of the Mesh folder. Setting the meshing defaults to a specified “physics” preference sets options in the Mesh folder such as Relevance Center, midside node behavior, shape checking, and other meshing behaviors. Note The Physics Preference is selectable from the Meshing Options panel only if the Meshing ap- plication is launched from a Mesh component system or a Mechanical Model component system. If the Meshing application is launched from an analysis system (whether it be via the Model cell in a non-Fluid Flow analysis system or the Mesh cell in a Fluid Flow analysis system), you must use the Details View of the Mesh folder to change the Physics Preference. See Determination of Physics, Analysis, and Solver Settings (p. 19) for more information. Mesh Method Setting the Physics Preference option also sets the preferred Mesh Method option for the specified physics. All of the meshing methods can be used for any physics type, however we have found that some of our meshers are more suitable for certain physics types than others. The preferred ANSYS Workbench Mesh Methods are listed below grouped by physics preference. Release 13.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information of ANSYS, Inc. and its subsidiaries and affiliates. 2 Capabilities in Workbench [...]... traditional ANSYS AUTODYN application (AUTODYN component system) Types of Meshing The following types of meshing are discussed in this section Meshing by Algorithm Meshing by Element Shape Meshing by Algorithm This section describes types of meshing in terms of two meshing algorithms: “patch conforming” and “patch independent” Patch Conforming What is patch conforming meshing? Patch conforming meshing is a meshing. .. with Meshing Application Parameters ANSYS Workbench and Mechanical APDL Application Meshing Differences Basic Meshing Application Workflows The following sections describe several basic workflows for using the Meshing application in ANSYS Workbench: Overview of the Meshing Process in ANSYS Workbench Overview of the Meshing Process for CFD/Fluids Analyses Combining CFD/Fluids Meshing and Structural Meshing. .. Meshing • MultiZone Mesher Cartesian Meshing • 6 CutCell Mesher Release 13 .0 - © SAS IP, Inc All rights reserved - Contains proprietary and confidential information of ANSYS, Inc and its subsidiaries and affiliates Conformal Meshing and Mesh Method Interoperability Quad Meshing • Quad Dominant • Uniform Quad/Tri • Uniform Quad Triangle Meshing • All Triangles Conformal Meshing Between Parts When meshing. .. native ANSYS Workbench data The following topics are addressed in this section: Basic Meshing Application Workflows Strategies for CFD/Fluids Meshing in ANSYS Workbench Accessing Meshing Functionality Overview of the Meshing Application Interface Determination of Physics, Analysis, and Solver Settings Working with Legacy Mesh Data Exporting Meshes or Faceted Geometry Extended ANSYS ICEM CFD Meshing. .. been set, the Meshing Options panel would be useful only for setting meshing defaults in the Options dialog box Thus if you uncheck Set Meshing Defaults, the Meshing Options panel cannot provide any additional functionality and the OK button is disabled Display This Panel at Meshing Startup This option controls whether the Meshing Options panel appears at startup of the Meshing application Meshing Implementation... This section describes the basic process for using the Meshing application to create a mesh as part of an ANSYS Workbench CFD/fluids analysis Refer to Strategies for CFD/Fluids Meshing in ANSYS Workbench (p 15 ) for information about different CFD/Fluids meshing strategies Refer to the ANSYS Workbench help for detailed information about working in ANSYS Workbench There are four basic steps to creating... - Contains proprietary and confidential information of ANSYS, Inc and its subsidiaries and affiliates 17 Usage in Workbench Overview of the Meshing Application Interface The intuitive Meshing application interface, which is shown in Figure: Meshing Application Interface (p 18 ), facilitates your use of all meshing controls and settings Figure: Meshing Application Interface The functional elements of... System (p 17 ) Note In the 13 .0 release, ANSYS AUTODYN runs inside the Mechanical application The recommendation is to use an Explicit Dynamics analysis system, in which meshing comes as part of that system As an alternative, you can also use this system to prepare a model for the traditional ANSYS AUTODYN application (AUTODYN component system) For simple ANSYS AUTODYN models, you can use the meshing. .. Combining CFD/Fluids Meshing and Structural Meshing Overview of the Meshing Process in ANSYS Workbench The following steps provide the basic workflow for using the Meshing application as part of an ANSYS Workbench analysis (non-Fluid Flow) Refer to the ANSYS Workbench help for detailed information about working in ANSYS Workbench 1 Select the appropriate template in the Toolbox, such as Static Structural... across parts is conformal Does not support match control 10 Release 13 .0 - © SAS IP, Inc All rights reserved - Contains proprietary and confidential information of ANSYS, Inc and its subsidiaries and affiliates Usage in Workbench The Meshing application is a separate ANSYS Workbench application The Meshing application is data-integrated with ANSYS Workbench, meaning that although the interface remains . Group 10 1 Nodes 10 1 Elements 10 1 Mesh Metric 10 1 Element Quality 10 6 Aspect Ratio Calculation for Triangles 10 6 Aspect Ratio Calculation for Quadrilaterals 10 7 Jacobian Ratio 10 8 Warping Factor 11 0 Parallel. 250 Contact Meshing 2 51 Winding Body Meshing 2 51 Wire Body Meshing 2 51 Pyramid Transitions 2 51 Match Meshing and the Symmetry Folder 2 51 Rigid Body Meshing 2 51 Thin Solid Meshing 254 CAD Instance Meshing. 11 0 Parallel Deviation 11 3 Maximum Corner Angle 11 4 Skewness 11 4 Orthogonal Quality 11 7 Local Mesh Controls 12 1 Method Control 12 2 Method Controls and Element Midside Nodes Settings 12 2 Setting the