Meshing User''''s Guide ANSYS phần 2 potx

Example of ANSYS FLUENT Workflow in ANSYS WorkbenchThis example illustrates the basic workflow you can follow to create a multibody part in the DesignModelerapplication, mesh the model i

For details about the boundary (face) zone and continuum (cell) zone types in ANSYS FLUENT,

refer to the documentation available under the Help menu within ANSYS FLUENT

Zone Type Assignment

This section describes zone naming and the zone type assignment process

• Names that begin with a digit are prefixed by “zone.”

• If the part name and the body name are identical, only the body name is used to create the zone name.The same rule applies to single body parts

If a zone was created for a Named Selection (as described in Classes of Zone Types in ANSYS FLUENT (p 25)),the name of the zone is set to the name of the Named Selection

In cases where the zone naming process could lead to conflicting zone names (for example, in a situationwhere the potential exists for a zone name that is already in use to be used to name a new zone), one ofthe following approaches is used:

• If the zone type is not similar to the zone name in question, the zone type will be prefixed to the zone

name to make it unique For example, an existing continuum zone named “fluid” and a new boundary

zone named “fluid” (with zone type WALL) will result in the boundary zone being renamed “wall-fluid.”

• If the zone type is similar to the zone name in question, a unique integer will be suffixed to the zone

name, preceded by an underscore character (_) For example, an existing continuum zone named “fluid”

and a second continuum zone named “fluid” (with zone type FLUID) will result in the second continuum

zone being renamed “fluid_1.” Subsequent continuum zones named “fluid” (with zone type FLUID) will

be renamed “fluid_2,” “fluid_3,” and so on

Zone Type Assignment Process

The zone type is derived from the zone name To assign zone types, the string comparison operations detailedbelow are performed during the export process These string comparison operations, which correspond tothe naming conventions described in Standard Naming Conventions for Naming Named Selections (p 27), areapplied in the order in which they are listed below (that is, at first an exact match is tested, after that a

partial match is tested, etc.) and are always case-insensitive For example, fluid, Fluid, FLUid, and FluID are all exact matches for the 'FLUID' string comparison and result in a zone type of FLUID being assigned.

When the search operation begins, it will start by searching the first portion (or sub-string) of the string and

if no match is found, it will search for a match anywhere in the string For example, if a Named Selection

with the name wall_inlet_flange is defined, it will be exported as zone type WALL The 'inlet' portion of the

name will have no effect on zone type assignment

Once they are exported, names are all lowercase The single quotation marks that are shown enclosing the

strings below are not considered during the string comparison operations

1 Exact matches are checked:

{'INLET' && 'VENT'}

{'INTAKE' && 'FAN'}

{'POROUS' && 'JUMP'}

{'PRESSURE' && 'FAR' && 'FIELD'}

Zone Type Assignment Process

{'PRESSURE' && 'INLET'}

{'PRESSURE' && 'OUTLET'}

'RADIATOR'

{'RECIRCULATION' && 'INLET'}

{'RECIRCULATION' && 'OUTLET'}

'SOLID'

'SYMMETRY'

{'VELOCITY' && 'INLET'}

3 String comparisons to the special abbreviations listed in the table below are performed if no matchwas found in step 1 or step 2 If an exact match to one of the strings listed in the table is found, thecorresponding zone type is assigned:

This zone type is assigned

When a match for this string is found

This zone type is assigned

When a match for this string is found

This zone type is assigned

When a match for this string is found

Ex-and finally Named Selections)

• Boundaries of bodies (that is, boundary or face zones) are assigned zone type WALL.

Special Cases

Be aware of the following special cases related to zone type assignment:

• If Physics Preference (p 57) is set to CFD and no other zone assignment has been explicitly defined, all

zones are exported as FLUID zones See FLUENT Mesh Export (p 23) for more information

• If the model includes an enclosure from the DesignModeler application, the enclosure body is assigned

a continuum zone type of FLUID by default.

• A boundary zone type of INTERIOR is assigned automatically between two FLUID zones (sharing a

common boundary) at the time of mesh export For this reason, you are not required to explicitly define

an INTERIOR zone in such cases.

• A boundary zone type of WALL is assigned automatically to a baffle, unless the baffle is part of a Named

Selection that was defined in the DesignModeler application or the Meshing application, and the name

of the Named Selection results in a different zone type assignment

• A boundary zone type of WALL is assigned automatically between a FLUID zone and a SOLID zone at the time of mesh export For this reason, you are not required to explicitly define a WALL zone in such cases ANSYS FLUENT will automatically generate an additional WALL SHADOW zone when reading the

mesh file

• Due to a limitation concerning the definition of rotational/translational periodicity in ANSYS Workbench,

the boundary zone type PERIODIC is always replaced by the boundary zone type WALL during the mesh

export process (However, the zone name is kept.) The suggested workaround is to manually redefineperiodic boundary conditions in ANSYS FLUENT For details, refer to the documentation available underthe Help menu within ANSYS FLUENT

Special Cases

Example of ANSYS FLUENT Workflow in ANSYS Workbench

This example illustrates the basic workflow you can follow to create a multibody part in the DesignModelerapplication, mesh the model in the Meshing application, and export the mesh to ANSYS FLUENT In the ex-ample, the bodies are renamed in the DesignModeler application, and Named Selections are defined in theMeshing application Based on these definitions, ANSYS FLUENT zone names/types are assigned correctlyand predictably (for both continuum and boundary zones) in the exported FLUENT mesh file

First, the model is imported into the DesignModeler application The model consists of nine solid bodiesafter import In the DesignModeler application, a multibody part is formed, the bodies are renamed, and allbodies are assigned a material property of fluid (See FLUENT Mesh Export (p 23) for more information about

the Fluid/Solid material property in the DesignModeler application.) Shared Topology is also used in this

example Refer to Figure: Multibody Part Containing All Fluid Bodies in the DesignModeler Application (p 32)

Figure: Multibody Part Containing All Fluid Bodies in the DesignModeler Application

Next, the model is edited in the Meshing application The patch conforming mesh method is applied withinflation, and Named Selections are defined for boundary zones Virtual Topology is also used in this example

to provide geometry cleanup Refer to Figure: Named Selections Defined in Meshing Application (p 33)

Figure: Named Selections Defined in Meshing Application

Finally, the model is edited in ANSYS FLUENT As shown in Figure: Boundary Zone Names and Types Transferred

to ANSYS FLUENT (p 34), the boundary zone names and types are transferred as expected

Special Cases

Figure: Boundary Zone Names and Types Transferred to ANSYS FLUENT

Similarly, continuum (or cell) zone names and types (in this case, all fluid) are transferred as expected Refer

to Figure: Continuum Zone Names and Types Transferred to ANSYS FLUENT (p 35)

Figure: Continuum Zone Names and Types Transferred to ANSYS FLUENT

POLYFLOW Export

When you export a mesh file to POLYFLOW format (File> Export from the Meshing application main menu, then Save as type POLYFLOW Input Files), a Patran-based mesh file with the extension poly is created.

The exported mesh file is suitable for import into POLYFLOW

Named Selections are not supported in the Patran-based format, so any Named Selections that were definedwill not appear in the POLYFLOW mesh Instead, the information from the Named Selections will be mappedinto Material IDs for bodies and Load IDs for faces

Element types that are supported in the exported POLYFLOW mesh are listed in the table below Only linearmeshes are supported for POLYFLOW export

Supported Element Type Dimension

8–node hexahedral3D

4–node tetrahedral5–node pyramid6–node wedge3–node triangle2D

POLYFLOW Export

Supported Element Type Dimension

When you export a mesh file to CGNS format (File> Export from the Meshing application main menu, then

Save as type CGNS Input Files), a CGNS mesh file with the extension cgns is created The exported meshfile is suitable for import into a CGNS-compatible application

Named Selections are supported in the CGNS file

Element types that are supported in the exported CGNS mesh are listed in the table below Only linearmeshes are supported for CGNS export

Supported Element Type Dimension

8–node hexahedral3D

4–node tetrahedral5–node pyramid6–node wedge3–node triangle2D

4–node quadrilateral

ICEM CFD Export

When you export from the Meshing application to ANSYS ICEM CFD format (File> Export from the Meshing application main menu, then Save as type ICEM CFD Input Files), an ANSYS ICEM CFD project file with the

extension prj, along with a geometry file (*.tin) and/or mesh file (*.uns) will be written This export

function-ality is designed such that consistent results are obtained between this export and the Workbench Readers

option in ANSYS ICEM CFD

ANSYS ICEM CFD part names that appear in the exported files are derived from the ANSYS Workbenchgeometry part and body names In the case of a single body part, only the body name is used

Note

The concept of a part in ANSYS Workbench and a part in ANSYS ICEM CFD is not the same For

information about parts in ANSYS Workbench, refer to Conformal Meshing Between Parts (p 7)

in the Meshing application help and Assemblies, Parts, and Bodies in the Mechanical help For

information about parts in ANSYS ICEM CFD, refer to the documentation available under the Helpmenu within ANSYS ICEM CFD

Anytime you plan to export from the Meshing application to ANSYS ICEM CFD format, it is best practice todefine the desired part and body names for your model in the DesignModeler application prior to meshingthe model in the Meshing application This is recommended because the ANSYS ICEM CFD part names will

be derived from the part and body names that are defined for the model when you initially open the model

in the Meshing application; the export process will ignore any renaming that occurs in the Meshing ation

applic-Note

As an alternative to the export process described here, you can save your ANSYS Workbench files

(*.mechdat or *.meshdat) and use the Workbench Readers option to load the files into ANSYS

ICEM CFD (as long as ANSYS Workbench and ANSYS ICEM CFD are installed on the same machine)

(Legacy formats such as *.dsdb and *.cmdb are also supported.) Any defined Named Selections

will be imported into ANSYS ICEM CFD as subsets and if they overlap, it will not result in a failure

In cases where there is overlap, you can clean up the subsets in ANSYS ICEM CFD and then convert

them into parts For details about handling imported ANSYS Workbench files in ANSYS ICEM CFD,

refer to the documentation available under the Help menu within ANSYS ICEM CFD

Rules Followed By the Export Process

When exporting to ANSYS ICEM CFD format, these rules are followed:

Note

The series of examples that follows this list illustrates many of the rules listed here

• To achieve unique ANSYS ICEM CFD part names in the ANSYS ICEM CFD format files, a unique integer

is suffixed to all ANSYS Workbench part/body names

• A single body part in ANSYS Workbench will appear as <part_name>_<part_index> in the ANSYS ICEM

CFD format files

• A multibody part in ANSYS Workbench will appear as dex> in the ANSYS ICEM CFD format files The / character denotes hierarchy.

<part_name>_<part_index>/<body_name>_<body_in-• Bodies that are in a multibody part in ANSYS Workbench are put into an ANSYS ICEM CFD assembly

The structuring in the ANSYS ICEM CFD format files reflects the part/body structure present in ANSYSWorkbench

• As long as they are not contained in Named Selections, faces that are shared between bodies in the

same multibody part in ANSYS Workbench are put into separate ANSYS ICEM CFD parts This type of

shared face is named according to the bodies having the face in common, with the body names separated

by the # character

• Entities that are contained in a Named Selection are put into a separate ANSYS ICEM CFD part

Note

For the export to work properly, an entity can be contained in only one Named Selection If

an entity is contained in more than one Named Selection, the export fails

• For each body, an ANSYS ICEM CFD Material Point is created and put into the corresponding ANSYS

ICEM CFD part The names of Material Points have the suffix _MATPOINT

• If a mesh has been generated, it is exported along with the geometry In such cases, these additional

rules are followed:

Rules Followed By the Export Process

As long as they are not contained in a Named Selection, node/line/surface mesh cells are associated

with the corresponding geometry part/body in ANSYS ICEM CFD

–

– As long as they are not contained in a Named Selection, volume mesh cells are associated with the

Material Point part

– Mesh cells that are associated with geometry entities that are contained in a Named Selection areassociated with the ANSYS ICEM CFD part that corresponds to that Named Selection

The first example is a model consisting of four separate single body parts in ANSYS Workbench The singlebody parts are named fluid1, fluid2, fluid3, and fluid4 The table below shows the geometry in ANSYS

Workbench and the corresponding part names that will appear in ANSYS ICEM CFD:

Results in these part names in ANSYS ICEM CFD

This geometry in ANSYS Workbench

A model consisting of four separate single body parts

named:

FLUID1_1fluid1

FLUID2_2fluid2

FLUID3_3fluid3

FLUID4_4fluid4

The figure below shows the model after it was meshed in the Meshing application:

Figure: Meshed Model (Four Separate Workbench Parts) Ready for Export to ANSYS ICEM CFD

Next, the model was exported from the Meshing application to ANSYS ICEM CFD format In the figure below,the corresponding prj file has been opened in ANSYS ICEM CFD Notice the names that are assigned to thevarious entities in the ANSYS ICEM CFD format file:

• Each body/part name has been suffixed with a unique integer to distinguish it from similarly named

bodies/parts (Note that in this example, part_name is equal to body_name.)

• Each single body part in ANSYS Workbench appears as <part_name>_<part_index> in the ANSYS ICEM

CFD format files For example, the part named fluid1 in ANSYS Workbench has a part name of FLUID1_1

in ANSYS ICEM CFD, which appears as FLUID1_1_1 in the ANSYS ICEM CFD format files after the

part_index is added.

• For each body in the ANSYS Workbench file (Fluid1, Fluid2, Fluid3, Fluid4), a Material Point has beenassigned (FLUID1_1_1_MATPOINT, FLUID2_2_1_MATPOINT, FLUID3_3_1_MATPOINT, FLUID4_4_1_MAT-POINT)

Figure: Opening the prj File (Four Separate Workbench Parts) in ANSYS ICEM CFD

The second example is a model consisting of one multibody part in ANSYS Workbench The multibody part,which is named Part 4, contains four bodies named fluid1, fluid2, fluid3, and fluid4 The table below showsthe geometry in ANSYS Workbench and the corresponding part names that will appear in ANSYS ICEM CFD:

Results in these part names in ANSYS ICEM CFD (the / character denotes hierarchy)

This geometry in ANSYS Workbench

A model consisting of one multibody part named

Part 4, containing four bodies named:

PART_4_1/FLUID1_3fluid1

PART_4_1/FLUID2_2fluid2

PART_4_1/FLUID3_1fluid3

PART_4_1/FLUID4_4fluid4

Rules Followed By the Export Process

Figure: Meshed Model (One Multibody Workbench Part) Ready for Export to ANSYS ICEM CFD

Next, the model was exported from the Meshing application to ANSYS ICEM CFD format In the figure below,the corresponding prj file has been opened in ANSYS ICEM CFD Notice the names that are assigned to thevarious entities in the ANSYS ICEM CFD format file:

• Each body/part name has been suffixed with a unique integer to distinguish it from similarly named

bodies/parts

• Each multibody part in ANSYS Workbench appears as dex> in the ANSYS ICEM CFD format files For example, the fluid1 body in Part 4 in ANSYS Workbench

<part_name>_<part_index>/<body_name>_<body_in-has a part name of PART_4_1/FLUID1_3 in the ANSYS ICEM CFD format files

• The bodies that are in the multibody part in the ANSYS Workbench file (fluid1, fluid2, fluid3, and fluid4)have been put into an ANSYS ICEM CFD assembly named Part_4

• The faces that are shared between the various pairs of bodies have been named FLUID2_2#FLUID1_3,FLUID3_1#FLUID2_2, and FLUID3_1#FLUID4_4

• For each body in the ANSYS Workbench file (fluid1, fluid2, fluid3, fluid4), a Material Point has been signed (FLUID1_3_MATPOINT, FLUID2_2_MATPOINT, FLUID3_1_MATPOINT, FLUID4_4_MATPOINT)

as-Figure: Opening the prj File (One Multibody Workbench Part) in ANSYS ICEM CFD

The third (and final) example involves a model for which four Named Selections are defined in the Modeler application The model is meshed in the Meshing application, exported to ANSYS ICEM CFD format,and opened in ANSYS ICEM CFD

Design-The first figure shows the model after it was meshed in the Meshing application

Figure: Meshed Model (with Named Selections) Ready for Export to ANSYS ICEM CFD

Rules Followed By the Export Process

The next four figures show the entit(ies) in the model that are contained in each of the four Named Selections.

In the figure below, the Fluid1_Fluid2 Named Selection is highlighted

Figure: Fluid1_Fluid2 Named Selection

In the figure below, the InterfaceSolidFluid2 Named Selection is highlighted

Figure: InterfaceSolidFluid2 Named Selection

In the figure below, the SharedEdge Named Selection is highlighted

Figure: SharedEdge Named Selection

In the figure below, the SharedVertices Named Selection is highlighted

Figure: SharedVertices Named Selection

Next, the model was exported from the Meshing application to ANSYS ICEM CFD format In the figure below,the corresponding prj file has been opened in ANSYS ICEM CFD Notice the names that are assigned to thevarious entities in the ANSYS ICEM CFD format file:

Rules Followed By the Export Process

• Each body/part name has been suffixed with a unique integer to distinguish it from similarly namedbodies/parts.

• The bodies that are in the multibody part in the ANSYS Workbench file (Solid, Fluid1, and Fluid2) havebeen put into an ANSYS ICEM CFD assembly named Part_1

• The face that is shared between SOLID_1 and FLUID1_2 has been named SOLID_1#FLUID1_2

• Because Fluid1_Fluid2, InterfaceSolidFluid2, SharedEdge, and SharedVertices are all Named Selections

in the ANSYS Workbench file, each of them has been put into a separate ANSYS ICEM CFD part

• For each body in the ANSYS Workbench file (Solid, Fluid1, Fluid2, Solid), a Material Point has been signed (SOLID_1_MATPOINT, FLUID1_2_MATPOINT, FLUID2_3_MATPOINT, and SOLID_2_1_MATPOINT)

as-Figure: Opening the prj File (with Named Selections) in ANSYS ICEM CFD

Note

For additional information, refer to the documentation available under the Help menu within

ANSYS ICEM CFD

Exporting Faceted Geometry to TGrid

You can use the Meshing application to export faceted geometry for use in TGrid:

1 Select File> Export from the main menu.

2 In the Save As dialog box, choose a directory and specify a file name for the file Then choose TGrid

Faceted Geometry File from the Save as type drop-down menu and click Save.

As a result, a file with the extension tgf is created The exported file can be imported into TGrid, where youcan use such features as the TGrid wrapper utility