Introduction to the
Computer ExercicesMMVN05
ROBERT SZASZ
Outline
• CFD ’in a nutshell’
• Introduction to
ANSYS® Workbench
Basic steps of CFD
gjhgjhgj Problem
Pre-processing
Solving
Post-processing
Control
Pre-processing
• What is the goal?
• Physics
– Compressible/incompressible
– Single/multi phase
– Gravity
– Reactions
– ...
• Governing equations
• Models
gjhgjhgj Problem
Pre-processing
Solving
Post-processing
Control
Pre-processing
• Geometry
– Isolate region of interest
» How small/big?
» 2D/3D
• Discretize
– Mesh
» Finite volumes/Finite differences
» Structured/Untsructured
– Discretization schemes
» Low order/High order
» Central/Upwind
gjhgjhgj Problem
Pre-processing
Solving
Post-processing
Control
Pre-processing
• Solution methods
– Explicit/implicit
– (Non)Coupled
– Single-core/parallell?
• Post processing settings
– What to save?
– How often?
gjhgjhgj Problem
Pre-processing
Solving
Post-processing
Control
Solution
• Start/submit
• Wait
• Wait
• Wait
• Monitor/control
• Adjust/wait
• Wait
• ...
• Go to post-processing
gjhgjhgj Problem
Pre-processing
Solving
Post-processing
Control
Post-processing
• Extract useful information
• What
– Pressure, velocity,
temperature, forces,...
• Where
– In points
– Along lines
– Cross-sections
– Iso-surfaces
• Properties
– Average, RMS, PDF, FFT,
animations, ...
gjhgjhgj Problem
Pre-processing
Solving
Post-processing
Control
Control
• Comparison
– Theory
– Experiments
– Other computations
• Check sources of error
– Models/equations
– Discretization
– Solution
– Post-processing
gjhgjhgj Problem
Pre-processing
Solving
Post-processing
Control
Outline
• CFD ’in a nutshell’
• Introduction to
ANSYS® Workbench
– Not a complete
overview
– Take notes and use
as quick reference
– Ask
Ansys Workbench
• Workbench:
connects individual
modules/softwares
• Easy transfer of
information
• Parametric studies
Ansys Workbench
2D vs 3D
Geometry
• DesignModeler
• SpaceClaim
• Import
Meshing
• FluentMeshing
• IcemCFD
• 3rd party
Solver
• Fluent
– Both ‘Setup’
and ‘Solution’
– Postprocessing
also can be
done here
Post-Processing
• Fluent
– Access to more
variables
• CFD Post
– Easier to
compare
several cases
Introduction to ANSYS ® Fluent
gjhgjhgj Problem
Pre-processing
Solving
Post-processing
Control
Geometry /Mesh/General
• If you receive a ready mesh
• File → Read → Case
• Check mesh
• Mesh → Check
• Mesh → Quality
Models
Turbulence
models
→
Viscous
E.g. When not converging
What do you want to check
during the computation ?
Initial values!
Convergence criteria set here
Start computations here
Maximum number of iterations,
Might stop before if converged!
Show mesh, isocontours, vectors
2D plots
Read in other
experimental / computed
data here!
Activate this if you want
to save data for later
comparison.
Save picture: File → Save Picture
Summary of settings: Report