a finite cylinder in a wind tunnel
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Xin Yan
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Show the regular access to external flow Set up a turbulent problem
Expressions
Additional choices for deal with the result
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A finite cylinder in a wind tunnel
L=1.5m W=1m H=1m D=0.1m h=0.3m D1=0.5m D2=0.5mAir at 25
Density: 1.185 [kg m^-3] Dynamic Viscosity:1.831e-5 [kg m^-1 s^-1]Inlet velocity:
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D
L
W
H
h
D2
D1
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Geometry: DesignModeler Pre-processor Mesh: CFX-Meshing
CFX-Pre
Solver CFX-Solver
Post-processor CFX-Post
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ANSYS workbench:DesignModeler (.agdb)
Modeling
1) Wind tunnel:
2) Cylinder: Cut material
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Create>Primitives>Box
Create>Primitives>Cylinder
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ANSYS workbench:DesignModeler (.agdb)
Modeling
1) Wind tunnel:
2) Cylinder: Cut material
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Create>Primitives>Box
Create>Primitives>Cylinder
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ANSYS workbench:CFX-Mesh
1) Specify regions
2) Set spacing for regions
3) Inflation mesh
4) Generate the surface &volume mesh
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ANSYS workbench:
CFX-Mesh
1) Specify regions
2) Set spacing for regions3) Inflation mesh
4) Generate the surface &volume mesh
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Cylinder PlateSpacing Max:0.005m
Min:0.001mMax:0.01Min:0.0037
Inflation 0.005 0.0075
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ANSYS workbench: CFX-Pre1) Create a domain
2) Set up boundary conditions
3) Set solver control
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ANSYS workbench: CFX-Pre1) Create a domain
2) Set up boundary conditions
3) Set solver control
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Outlet: outlet>average static pressure 0 PaWalls: wall>free slipCylinder & plate: wall>no slipInlet: inlet>normal speed>velocity profile
>Intensity=1%
Help: Expression language
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ANSYS workbench: CFX-Pre
1) Create a domain
2) Set up boundary conditions
3) Set solver control
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ANSYS Workbench: CFX-Solver
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Why?Increase accuracy
Where?
Near wall area whereyou are interested in.
How?
Insert inflated boundary.
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Inlet
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Assume 1/7th power law:
[1]http://www.see.ed.ac.uk/~johnc/teaching/fluidmechanics4/2003-04/fluids9/2-dboundary.html
[1]
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Outlet & Opening Outlet: the flow is predominantly directed out of the domain.
Opening: allows the fluid to cross the boundary surface ineither direction.
Wall No-slip: velocity of the fluid at the wall boundary is set to
zero.
Free-slip: the velocity component parallel to the wall has afinite value (which is computed), but the velocity normal to
the wall is zero.
Symmetry
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ANSYS Workbench: CFX-Solver
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ANSYS Workbench: CFX-post1) Contour and vector of velocity in the plane
of z=0.5m.
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ANSYS Workbench: CFX-post2) Streamline of velocity in the plane of y=1.5m.
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ANSYS Workbench: CFX-post3) Streamline of 2-D velocity (v&w) in the plane
of x=0.58m.
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ANSYS Workbench: CFX-post4) Contour of turbulence kinetic energy (k) and
vorticity (x) in the plane of x=0.58m.
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ANSYS Workbench: CFX-post5) Quick animation
Streamlines
Planes
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Finish the simulation Capture the picture of streamline with two
vortexes in the plane parallel to the plate.
Capture another picture which you areinterested in and give a brief introduction ofthis picture, include the plane location andthe feature in the picture.
Due day: 13/10/2010
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