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14. 5 Release

Introduction to ANSYS CFD Professional

Lecture 03 Introduction to ANSYS Meshing

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Preprocessing Workflow

Sketches and

Planes

Geometry Import

Options

3D Operations

Direct CAD/Bi-

Directional CAD

Geometry

Cleanup and

Repair

Automatic

Cleanup

Merge, Connect,

Projection, Flow

Volume

Extraction, etc

Extrude, Revolve,

Sweep, etc

3D Operations

Boolean, Body

Operations, Split,

etc

Meshing

Methods

Hybrid Mesh: Tet,

Prisms, Pyramids

Hexa Dominant,

Sweep meshing

Global Mesh

Settings

Local Mesh

Settings

Sizing,

Body/Sphere of

Influence, Match

Control, etc

Geometry Creation OR

Geometry Import

Geometry Operations

Meshing Solver

Assembly

Meshing

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What is ANSYS Meshing?

ANSYS Meshing is a component of ANSYS Workbench

• Next generation meshing platform

• Combines and builds on strengths of preprocessing offerings from ANSYS: ICEM CFD, TGRID, CFX-Mesh, Gambit

Creates Meshes for different Physics and Solvers

• CFD: Fluent, CFX and POLYFLOW

• Mechanical: Explicit dynamics, Implicit

• Electromagnetic

Integrates directly with other WB systems

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Physics, Sizing, Inflation, Pinch, etc.

Sizing, Refine, Pinch, Inflation, etc

Preview Surface Mesh, Inflation

Mesh Metrics, Charts

Meshing Process in ANSYS Meshing

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ANSYS Meshing Graphics User Interface

Units Bar Entity Details Bar Status/Info Bar

Toolbars

Outline

Details View

Graphics Window

Message Window

Selection Information

Section Planes

Mesh

Metrics

Worksheet

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• The geometry must comprise 3D solid bodies

• Surface bodies can be included to represent thin walls, provided that they are contained in the same part as the surrounding solid body (possible in DesignModeler)

• Otherwise additional steps must be taken in the CAD tool to convert surface bodies to 3D solids

Geometry Requirements

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Cutaway view of

fluid region

Body enclosing

PCB created

Circuit board

model

Geometry Requirements

• For CFD analyses, the geometry must represent the fluid region(s)

• It might be necessary to extract the fluid volume(s) from the original CAD

• If heat transfer through the solid components is important, then those bodies are retained and meshed too

External fluid region

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CAD for engine block

Geometry Requirements

Body created to fill void

Internal fluid region

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Two Meshing Approaches

• Part/Body based

– Meshing occurs at part or body level.

– Meshing Methods are scoped to individual bodies.

– Method assignment can be automatic or manual. Bodies contained in one part are conformally meshed.

• Assembly Meshing

– Meshes an entire model (assembly of parts) in one process.

– Capable of performing boolean operations including volume filling, intersection & combination.

– Conformal mesh created across parts.

• Part/Body Meshing & Assembly Meshing not interoperable.

• This course covers Part/Body based meshing

Meshing for 3D Geometry

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Meshing Methods for 3D Geometry - Examples

Sweep Meshing

Multizone Meshing

Tetrahedral Mesh

Automatic (Tetrahedral &

Sweep)

Methods covered in this course

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How to Generate a Mesh

• Right click Mesh in the tree for context menu

• Generate Mesh

– Generates entire volume mesh on all bodies

– Right click on individual bodies to generate mesh on selected body

• Preview

– Generates surface or inflation mesh only

• Allows surface or inflation mesh quality to be checked before volume meshing

• Not available when using Patch Independent Tetrahedron, MultiZone.

Mesh Generation

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Parameterized Meshing controls

• Global controls and local controls

• Selection of parameter promotes the parameter to the WB project page

• Geometry and Meshing parameters can be related using expressions in the parameter manager

• Example – Parameterized edge sizing

Parameterization in ANSYS Meshing

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• In this example the parameterised edge sizing is expressed as a function of the length parameter (from CAD package). Expressions created in Workbench.

Parameterization Example

Number of Divisions = 10 x Length

Length = 1m Divisions = 10

Length = 1.5m Divisions = 15

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• Used to assign a name to one or more selected entities

– Easy to reselect groups that will be referenced often

– Automatically transferred to CFX-Pre

• Named Selections can be applied to the entities of the same size, type or location, by using selection options

• A worksheet enables selection criteria to be modified

Named Selections