CFX-4
Introductory Training (Dec 1999)
1-1
CFX-4.3 V4.3.1H
Lecture 1
Introduction
CFX-4
Introductory Training (Dec 1999)
1-2
CFX-4.3 V4.3.1H
Performing a CFD Analysis
? Define the problem
Geometry
> Domain in which the governing equations will be solved
and solutions obtained
> Creation of multi-block structure.
Grid
> The geometry is split into many small volumes or cells
forming a grid or mesh
> Conservation of mass,momentum,energy,etc,are
satisfied locally in each cell.
> U,V,W,P,T,etc,are defined at the center of each cell,
i.e,collocated grid
> CFX-4 grids are,body-fitted” and,multi-block”.
CFX-4
Introductory Training (Dec 1999)
1-3
CFX-4.3 V4.3.1H
Performing a CFD Analysis
Boundary conditions
> Needed on all external surfaces of geometry.
Physical considerations
> Fluid properties such as density and viscosity
> Selection of models such as k-e for turbulence,
combustion models,etc.
Multi-block grid
CFX-4
Introductory Training (Dec 1999)
1-4
CFX-4.3 V4.3.1H
Performing a CFD Analysis
? Calculate the flow
Flow solver options
and parameters have
to be defined
Governing equations
are solved
Dynamic monitoring
of solution history
Convergence has to
be obtained.
CFX-4
Introductory Training (Dec 1999)
1-5
CFX-4.3 V4.3.1H
Performing a CFD Analysis
? Examine the results
Either in numerical or graphical format.
CFX-4
Introductory Training (Dec 1999)
1-6
CFX-4.3 V4.3.1H
CFD Analysis Using CFX-4
? Pre-Processors,
CFX-Build
CFX-Meshimport:
> Block structure
optimization
> Radiation
geometry file
> Import mesh
from IDEAS/
PATRAN
CFX-Setup.
CFX-ENVIRONMENT
CFX-4
Introductory Training (Dec 1999)
1-7
CFX-4.3 V4.3.1H
CFD Analysis Using CFX-4
? Solver,CFX-4
Batch process.
? Post-Processor,CFX-Visualise /
CFX-Analyse
Interactive
Interface to other packages:
> PLOT3D,AVS,WAVEFRONT,
IDEAS LEVEL VI,IDEAS Master
Series,PATRAN,FIELDVIEW.
CFX-4
Introductory Training (Dec 1999)
1-8
CFX-4.3 V4.3.1H
CFX-Build Features
? CAD import
IGES
ProE,PATRAN Neutral,Unigraphics,CATIA,
CADDS.
? Parametric capabilities.
? Completely menu driven graphical user
interface (very intuitive).
? Context sensitive online help.
CFX-4
Introductory Training (Dec 1999)
1-9
CFX-4.3 V4.3.1H
Physical Models in CFX-4
? Steady/Transient flow
? Laminar flow
? Turbulent flow
k-e
Low Re k-e
Low Re K-omega
RNG k-e
Algebraic Reynolds stress
Differential Reynolds stress
Reynolds flux
? (Conjugate) Heat transfer
? Compressible flow
Weakly compressible
Fully compressible
? Buoyancy
Boussinesq approx.
Full buoyancy for
compressible flow
? Scalar transport (active &
passive)
? Non-Newtonian models
Power law
Bingham plastic
Bird-Carreau
Cross
Herschel-Bulkley
CFX-4
Introductory Training (Dec 1999)
1-10
CFX-4.3 V4.3.1H
Physical Models in CFX-4
? Cartesian or cylindrical
coordinates
? Rotating coordinates
? Sliding grid (combination
of rotating/stationary mesh)
? Multi-phase flows
Homogeneous
> Free surface,surface
tension
Multi-fluid
> MUSIG
Solidification
? Particle transport
Spray drier model
Coal & oil combustion
? Combustion
Mixed is burnt
> Coal combustion
> Oil combustion
> NOx model
Eddy break up
> Magnussen soot model
? Chemical kinetics
Link with PFDReaction
? Porous media
? Radiation (optional)
Discrete transfer
Monte Carlo
Grey / non-grey model
CFX-4
Introductory Training (Dec 1999)
1-11
CFX-4.3 V4.3.1H
Physical Models in CFX-4
? Unlimited extension through
user Fortran
? Property databases
PCP
INFOCHEM / DIPPR (optional)
CFX-4
Introductory Training (Dec 1999)
1-12
CFX-4.3 V4.3.1H
CFX-4 Flow Solver Features
? Finite-volume approach,collocated grid.
? SIMPLE,SIMPLEC,or PISO velocity-pressure
correction formulations.
? Discretization of time dependent terms
Fully implicit backward differencing (default)
Crank-Nicolson
Fixed or adaptive time-stepping.
? Various schemes for the convection terms.
? Linear solver methods
Algebraic multi-grid (AMG),Conjugate gradient
(ICCG),Stone,Block Stone,Line relaxation.
CFX-4
Introductory Training (Dec 1999)
1-13
CFX-4.3 V4.3.1H
Boundary Conditions in CFX-4
? Walls - temperature,heat flux,no slip,free slip.
? Flow boundaries:
Pressure,mass flow rate,velocity.
? Symmetry planes.
? Periodic planes.
? Internal baffles (thin surfaces).
? Solids,conducting solids,porous regions.
CFX-4
Introductory Training (Dec 1999)
1-14
CFX-4.3 V4.3.1H
CFX-Visualise Features
? Based on AVS (Advanced Visual Systems).
? Full 3D views of the model.
? Advanced light shading,fast geometry
rendering.
? Generation of iso-surfaces,slices (filled
contours),streamlines,vectors,surface
contours,line-graphs,probes,animations.
? Mouse driven interface combined with precise
numerical control.
CFX-4
Introductory Training (Dec 1999)
1-15
CFX-4.3 V4.3.1H
CFX-Analyse Features
? GUI-based quantitative post-processing tool
Command language for quantitative analysis
Allows the sequences of commands to be
encapsulated into macros.
? Also contains a wide range of graphic features
Isosurfaces
Velocity vector,contour and fringe plots
Relief maps
Streak lines and particle tracks
X - Y graphs
OpenGL-based 3-D viewer
Multiple viewing ports.
CFX-4
Introductory Training (Dec 1999)
1-16
CFX-4.3 V4.3.1H
CFX-4 File Hierarchy
CFX-
Build
Command
File
restartGeometry
File
FORTRAN
(optional)
Dump
File
Output
File
CFX-
Visualise
CFX-
Setup
CFX-
Meshimport
CFX-4
CFX-
Analyse
CFX-4
Introductory Training (Dec 1999)
1-17
CFX-4.3 V4.3.1H
CFX-4 File Nomenclature
problem.db -- CFX-Build database file (binary)
problem.db.jou -- CFX- Build database journal file
cfxbuild4.ses.## -- CFX- Build session file
m##.geo -- geometry file
m##.fc -- command file
m##.f -- fortran file
m##.fo -- output file
m##.dmp -- dump file (binary / ascii)