e2 ws2 wingbody prismv12
TRANSCRIPT
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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
WS5.2-2ANSYS, Inc. Proprietary 2009 ANSYS, Inc. All rights reserved.
July 2009Inventory #002664
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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Prism Meshing Workshop 2
WS5.2-3ANSYS, Inc. Proprietary 2009 ANSYS, Inc. All rights reserved.
July 2009Inventory #002664
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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Prism Meshing Workshop 2
WS5.2-4ANSYS, Inc. Proprietary 2009 ANSYS, Inc. All rights reserved.
July 2009Inventory #002664
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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Prism Meshing Workshop 2
WS5.2-5ANSYS, Inc. Proprietary 2009 ANSYS, Inc. All rights reserved.
July 2009Inventory #002664
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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Prism Meshing Workshop 2
WS5.2-6ANSYS, Inc. Proprietary 2009 ANSYS, Inc. All rights reserved.
July 2009Inventory #002664
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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Prism Meshing Workshop 2
WS5.2-7ANSYS, Inc. Proprietary 2009 ANSYS, Inc. All rights reserved.
July 2009Inventory #002664
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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Prism Meshing Workshop 2
WS5.2-8ANSYS, Inc. Proprietary 2009 ANSYS, Inc. All rights reserved.
July 2009Inventory #002664
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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Prism Meshing Workshop 2
WS5.2-9ANSYS, Inc. Proprietary 2009 ANSYS, Inc. All rights reserved.
July 2009Inventory #002664
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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Prism Meshing Workshop 2
WS5.2-10ANSYS, Inc. Proprietary 2009 ANSYS, Inc. All rights reserved.
July 2009Inventory #002664
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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Prism Meshing Workshop 2
WS5.2-11ANSYS, Inc. Proprietary 2009 ANSYS, Inc. All rights reserved.
July 2009Inventory #002664
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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Prism Meshing Workshop 2
WS5 2-12ANSYS, Inc. Proprietary 2009 ANSYS Inc All rights reserved
July 2009Inventory #002664
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