E2 WS2 Wingbody PrismV12

7/29/2019 E2 WS2 Wingbody PrismV12

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WS5.2-1ANSYS, Inc. Proprietary 2009 ANSYS, Inc. All rights reserved.

July 2009Inventory #002664

Chapter 5

Prism Meshing

Workshop 2Wingbody

ICEM CFD IntroductoryCourse


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Prism Meshing Workshop 2



Training ManualBottom up Volume Meshing

First, extrude prism mesh from

standalone surface mesh

Bottom up approach

Could also extrude into existingvolume mesh (traditional method),

top down approach

Generate rest of grid

Farfield volume

Delauney

Use density region

Define mesh size for refinement

In area where no geometry exists

Create Hexa core

For majority hex fill in far field

Choose File > Open Project

To load previously saved surfacemesh and geometry

Browse to Wingbody workingdirectory

Load previous project

If previous project was not completed, load the

geometry F6_complete.tin and the meshf6_surf.uns


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Training ManualGlobal Prism Parameters

Set global prism parameters

Mesh > Global Mesh Setup > PrismMeshing Parameters

Set Growth law to exponential (default)

Initial height =0

Height determined automatically sothat last prism is similar volume to

adjacent tetra

Proportional to size of triangle

Height ratio =1.2

Number of layers =5

New volume part =LIVE

Scroll down to access

We will create prism from a surface-only mesh

The volume part is necessary when

extruding from surface mesh


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Training ManualPick Parts for Prism Mesh

Select Parts and Compute prism mesh

Mesh > Compute Mesh > Prism Mesh

Press Select Parts for Prism Layer

FAIRING, FUSELAGE, WING

Apply, then Dismiss

Compute

Height, height ratio, and

num layers were set

globally


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Training ManualDisplay Mesh

Display Prism mesh

Turn off FARFIELD

Zoom in to view prism quadfaces on symmetry plane

Turn on Mesh > Volumes>Prisms in model tree

There is no other volumemesh but prisms

Unstructured mesh, prism.uns is

saved automatically to the working

directory


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Training ManualPrepare for Density Region

Create density region to define more

refined mesh behind wing

X = 150

X = 200

First

Second

Turn offMesh, turn on Geometry > Points and Curves

First create points behind wing

Select Geometry > Transform Geometry

Select first method: Translate Geometry

Copy= on

Method = Explicit, X Offset = 200

Select the first point shown below, and Apply

Select the second point, change X Offset to 150, Apply

If you have

trouble

selecting

points, turn off

curve selection


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Training ManualCreate Density Region

Select Mesh > Create Mesh Density

Set Size =5

Ratio =1.2

Width =5

Element size of 5 within density region, 5 layers(width) of size 5 outside of density region,expansion ratio of 1.2 away after 5 layers

In this case, the density region is planar, so the

virtual region is defined by the width and size SelectDensity Location > From: Points and select the

5 points as shown (any order)

Three along wing

Two just created behind wing

Apply


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Training ManualCompute Mesh

We now need to fill the volume between

the prisms and the farfield surface mesh

Select Mesh >Compute Mesh > VolumeMesh

Change Mesh Method to Quick (Delaunay)

Compute

Check Delaunay settings first

Mesh > Global Mesh Setup >Volume Meshing Parameters

Mesh Method = Quick(Delaunay)

Memory scaling factor = 1

Spacing scaling factor = 1


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Training ManualView Mesh Cut Plane

Select Mesh > Cut Plane > ManageCut Planein the Model Tree

Change Method to by 3 Locations

Select 3 locations defining a plane

perpendicular to the wing, through the

wing

Turn on

Volumes

Rotate to side

view

Note refinedmesh behind

wing

Prisms

immediately

around wing


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Training ManualSmooth Mesh

Improve overall mesh quality

Select Edit Mesh > Smooth Mesh Globally

Note Histogram

In lower right hand corner

Initial poor quality

In panel,Freeze TRI_3, PENTA_6, QUAD_4 Types

Try and retain elongated elements along wing

Use default forSmoothing iterations, Up to ValueandCriterion

Apply

Note change in histogram after complete Try changingUp to Valueto 0.3


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Training ManualReplot Histogram and Smooth Everything

Replot histogram

Right mouse select anywhere inhistogram window

Select Replot

Change values in Replot pop up window Min X= 0.0

Max X= 1.0

Max Y height= 25 So you can see bars with smaller number of

cells

Set all types toSmooth

Apply twice (10iterations total)


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WS5 2-12ANSYS, Inc. Proprietary 2009 ANSYS Inc All rights reserved


Training ManualHexa Core

Refill the volume with a hexa-core mesh

Turn on Hexa-Core for LIVE in Mesh > PartMesh Setup

Apply and Dismiss

Recompute mesh

With Create Hexa-Coretoggled on

Will grow hexa elements within designated volume

part(s)

Ignores density region

Documents

E2 WS2 Wingbody PrismV12