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