need to be developed using the Massage Passing
Interface (MPI) Standard
to transfer data between
different blocks.
•
Post-processing: 1. Visualize
the CFD results
(contour, velocity vectors, streamlines, pathlines,
streak lines, and iso-surface in 3D, etc.), and
2. CFD
UA
: verification and validation using EFD data (more
details later)
•
Post-processing usually through using commercial
software

27
Types of CFD codes
•
Commercial CFD code
: FLUENT, Star-
CD, CFDRC, CFX/AEA, etc.
•
Research CFD code
: CFDSHIP-IOWA
•
Public domain software
(PHI3D,
HYDRO, and WinpipeD, etc.)
•
Other CFD software includes the Grid
generation software (e.g. Gridgen,
Gambit) and flow visualization
software (e.g. Tecplot, FieldView)
CFDSHIPIOWA

28
CFD Educational Interface
Lab1: Pipe Flow
Lab 2: Airfoil Flow
Lab3: Diffuser
Lab4: Ahmed car
1. Definition of “CFD Process”
2. Boundary conditions
3. Iterative error
4. Grid error
5. Developing length of laminar
and turbulent pipe flows.
6. Verification using AFD
7. Validation using EFD
1. Boundary conditions
2. Effect of order of accuracy
on verification results
3. Effect of grid generation
topology, “C” and “O”
Meshes
4. Effect of angle of
attack/turbulent models on
flow field
5. Verification and Validation
using EFD
1. Meshing and iterative
convergence
2. Boundary layer
separation
3. Axial velocity profile
4. Streamlines
5. Effect of turbulence
models
6. Effect of expansion
angle and comparison
with LES, EFD, and
RANS.
1. Meshing and iterative
convergence
2. Boundary layer separation
3. Axial velocity profile
4. Streamlines
5. Effect of slant angle and
comparison with LES,
EFD, and RANS.

29
CFD process
•
Purposes
of CFD codes will be different for different
applications: investigation of bubble-fluid interactions for
bubbly flows, study of wave induced massively separated
flows for free-surface, etc.
•
Depend on the specific purpose and flow conditions of the
problem, different
CFD codes
can be chosen for different
applications (aerospace, marines, combustion, multi-phase
flows, etc.)
•
Once purposes and CFD codes chosen, “
CFD process
” is
the steps to set up the IBVP problem and run the code:
1. Geometry
2. Physics
3. Mesh
4. Solve
5. Reports
6. Post processing

30
CFD Process
Viscous
Model
Boundary
Conditions
Initial
Conditions
Convergent
Limit
Contours
Precisions
(single/
double)
Numerical
Scheme
Vectors
Streamlines
Verification
Geometry
Select
Geometry
Geometry
Parameters
Physics
Mesh
Solve
Post-
Processing
Compressible
ON/OFF
Flow
properties
Unstructured
(automatic/
manual)
Steady/
Unsteady
Forces Report
(lift/drag, shear
stress, etc)
XY Plot
Domain
Shape and
Size
Heat Transfer
ON/OFF
Structured
(automatic/
manual)
Iterations/
Steps
Validation
Reports

31
Geometry
•
Selection of an appropriate coordinate
•
Determine the domain size and shape
•
Any simplifications needed?
•
What kinds of shapes needed to be used to
best resolve the geometry? (lines, circular,
ovals, etc.)
•
For commercial code, geometry is usually
created using commercial software (either
separated from the commercial code itself, like
Gambit, or combined together, like FlowLab)
•
For research code, commercial software (e.g.
Gridgen) is used.