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Transcript of Plan for today (two exercises) 1: CAD, CFD, FEM · Numerical Methods in Aerodynamics Lecture 3:...
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
1
Plan for today (two exercises)
1: CAD, CFD, FEM
Fluid-Structure interaction (FSI)
http://www.ansys.com/solutions/fluid-dynamics.asp
http://www-harwell.ansys.com/demoroom/details.php?id=11,112
Create an object in SolidWorks (CAD)
Transfer the object to ANSYS Workbench
Generate a wind tunnel inclosure
Generate a fluid flow mesh
Apply boundary conditions
Apply initial conditions
Solve the flow around the object
Generate flow results
Solve the structural model
mesh, material, supports, pressure load from the fluid solution
Change the system and update the solution
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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Create room with mechanical inlet
Define variables for the inlet properties
Generate a fluid mesh of the room
Apply boundary conditions
Apply initial conditions
Solve the flow in the room
Generate flow results
Change the boundary conditions
Plan for today (two exercises)
2: Indoor environmental
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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Problem 1: Combining CAD, CFD and FEM
Solve the deformations due to flow pressure
Change the width of the structural element
Fixed support
Inflowsteel part
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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Create object in Solidworks
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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ANSYS Workbench an overview of the various parts in the
project
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Wind tunnel enclosure in DesignModeler
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Generating the mesh for the fluid flow applying boundary
conditions in CFX Pre
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Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Solve the fluid flow i CFX Solver
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Illustrate flow results in CFX Post
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Pressure result on boundary
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Transfer pressure from CFX to ANSYS structural solver and
solve for deformations
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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Solution of structural analysis
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Change the system
Change the CAD model
Update the geometry in CFX
Update the mesh
Adopt the boundary conditions from previous simulation
Solve for pressure
Update the geometry in the FEM model
Import the updated pressure
Solve the structural system
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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Problem 2: Indoor environmental solution
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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Create the model
Start SolidWorks (SW)
Create a new "part"
Chose "Top plane"
press "Sketch"
press "rectangle"
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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Create rectangle
Create a rectangle from the origo
press "smart dimension", click on the right and top side of the
rectangle and enter dimension=1m
press "zoom to fit"
Close the sketch and accept by clicking in the upper right corner
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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Extrude
press "features" and mark the sketch, press "Extruded Boss"
Extrude 5m and accept
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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Camfer the roof
Press "Features" and "Chamfer"
Chose top face of extruded shape
D=0.3m, angle = 45 degrees, accept
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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Save and transfer to Workbench
Save the part as "test1"
> ANSYS 11.0 > Workbench
NB! SolidWorks should be installed first in order to have the ANSYS
menu bar. Rerun the ANSYS installation and include the Solidworks
geometry interface, if it is missing
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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ANSYS Workbench
Open an empty project
Link to Active CAD Geometry
test1.SLDRT
New Geometry (This is already done if transfered directly from SW)
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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DesignModeler “New Geometry”
Press "Generate" to import the
SW part
Choose Attach1 >tools>freeze
For the tunnel part not to merge
with the element
Create a wind tunnel inclosure
ZXPlane
Sketching
Make rectangle (any size)
The rectangle should have a
corner in each quadrant
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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Set dimensions of the enclosure
Choose dimensions, Length/distance
L1 (positive x-direction) 20000 mm
L2 (negative x-direction) 10000 mm
L3 (positive z-direction) 10000 mm
L4 (negative z-direction) 10000 mm
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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Extrude the tunnel and cut out the body Extrude FD = 10000 mm (Generate to see result)
Cut out the body to leave just the region of interest for the CFD
Choose create>Body operations
Set Type to cut material and bodies to "test1" (select in the tree view or
box select)
Generate to see result
Save and return to "project" tab
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Generate the mesh (CFX-Mesh)
Generate regions
Right-click on regions>insert>composite 2D regions
Name Inlet (YZ low x), name outlet (YZ high X), name Free (top and two sides,
use ctrl to mark several surfaces), name building is the body (choose with box
select), name wall (XZ low Y)
Free
Inlet
outlet
WallBuilding
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Setting up the mesh
Define a maximum spacing
Default body spacing, maximum
spacing = 1600mm
Finer mesh around the body
Right-click spacing>insert>Face
Spacing
Select the body, apply
Face Spacing Type: constant
Constant edge length: 200 mm
Boundary layer around body and
wall
Right-click
inflation>insert>inflated boundary
choose body and wall (hold ctrl)
set Maximum thickness: 50 mm
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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Previewing the mesh, generate the mesh
Right-click on preview>insert>Preview group
Choose Free, Wall, Body > apply
Right-click on the preview>generate this surface mesh
Click on "generate the volume mesh for the current problem"
Return to the "Project" tab
Inflation layer
Wall
Free
Body
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Start the Advanced CFD (CFX-pre)
Create a domain "test1"
General option:
Domain models>pressure>reference pressure : 1 atm
Fluid models:
Heat Transfer Model>option Isothermal: Fluid temperature: 25 C
Turbulence model>option: shear stress transport
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Creating the boundary conditions
Click "create boundary condition": Inlet
Basic settings
Boundary type: Inlet
Location: Inlet
Boundary details
Mass and Momentum>Normal speed: 15 m/s
Turbulence>option: Intensity and length scale
Turbulence>medium turbulence intensity
Click "create boundary condition": Outlet
Basic settings
Boundary type: Outlet
Location: Outlet
Boundary details
Mass and Momentum>Option: Static pressure
Mass and Momentum>Relative Pressure: 0 Pa
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Click "create boundary condition": Free
Basic settings
Boundary type: Wall
Location: Free
Boundary details
Wall Influence on Flow>Option: Free Slip
Click "create boundary condition": Wall
Basic settings
Boundary type: Wall
Location: Wall
Boundary details
Wall Influence on Flow>Option: No Slip
Click "create boundary condition": Building
Basic settings
Boundary type: Wall
Location: Building
Boundary details
Wall Influence on Flow>Option: No Slip
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Setting initial values, solver control, and start the solver
Click "Define the global initial conditions":
Cartesian Velocity components>option: Automatic with value
U = 15 m/s
V = 0 m/s
W = 0 m/s
Turbulence Eddy Dissipation: select
Click "Define the solver control criteria":
Convergence control
Timescale control: automatic timescale
Timescale factor: 1 s
Max. iterations: 100
Click "Write solver file":
Operation: Start solver manager
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Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Viewing results
Choose "CFX Post", load result (*.res file)
Creating a sample plane, click location>plane
Definition: points and normal, point (1.5, 3, -0.5), normal (1, 0, 0)
Plane bounds: rectangular (x-size=6 m, y-size=3 m)
Plane type, sample (x-sample=50, y-sample=20)
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Vector plot of velocities, etc.
Click "create vector plot"
Location: plane 1
Variable: velocity
Same approach for other planes try "contour" or "streamline"
To see pressure on body create a new contour, location: building
For an animation click "show animation editor"
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Structural analysis
Create a new project link to active CAD geometry (Part1) and press
"New simulation"
Run the structural simulation Wizard
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Export body pressure to finite element model
Stress analysis > static structural
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Structural loads
Mark the building (not the bottom)
CFX loads > CFX pressure (browse for the res-file)
Apply supports (fixed at bottom)
Right-click on solution and insert “deformation>total”
solve
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Viewing the results
Click "total deformations"
Choose a scale factor 5xauto
Choose edges>show undeformed model
Click animation fan for animation of the result
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Change the model in SW
Double-click on the sketch
Double-click on the z-dimension
change to 2 m
Update by clicking "rebuild"
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Update the CFX-designModeler
Open the DesignModeler
Choose the attached geometry
Refresh>Using DesignModeler parameter values
Click "generate"
The new geometry is now included in the model
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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Update the CFX-mesh
Click "update the geometry from its original source"
Look at the preview group (right-click and generate)
Generate a new volume mesh
save as "test2"
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Update the CFX-pre
Press the "project" tab. Choose the CFX-pre file (building.cfx)
Re-read mesh file, file to load "building2.gtm"
Click "Write solver file":
Operation: Start solver manager
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Update the CFX-post
Open the CFX-post (*.cst)
Load results (test2_001.res)
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
environmental
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Update and solve the finite element model
Open the structural simulation
Update the geometry
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Update and solve the finite element model
Update the pressure
choose define as>CFX Results
Correct the filename to "building_002.res"
"Solve"
Numerical Methods in Aerodynamics
Lecture 3: Exercise CAD, CFD, FEM, Indoor
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Thank you for your attention