Home  General User Tips Working with Multiple Simulations in a DTF File
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Working with Multiple Simulations in a DTF File |
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One feature of the DTF file format is that multiple
simulations can be stored in a single DTF file. In
most cases, you will be working with multiple
simulations when you are running parallel
computations. This is due to the fact that you must
decompose the original mesh to obtain the decomposed
mesh. The decomposed mesh will be stored in a new
simulation in the DTF file. For more information on
decomposing a DTF file, please click
here to read the tip on decomposing DTF files.
This tip will discuss how to view and delete
simulations in a DTF file.
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DTF Information (DTF -i
option):
The DTF -i option will provide general information
about the content of the DTF file, such as number of
simulations, number of zones in a simulation, number
of cells per zone, zone type (structured or
unstructured), etc. This information can be useful
when running parallel computations since you can
check the cell count for each zone to be sure load
balancing has been achieved (most dtf_decompose
options automatically load balance). The usage for
the DTF utility is:
DTF -[command] modelname.DTF
For the -i option, the usage is:
DTF -i modelname.DTF
For this tip, I will be using a file named test.DTF.
When you execute the DTF -i command you will be the
following information:
Figure 1. Command line snippet showing DTF -i
option output
General information about the file, such as name,
title, date of creation, etc. is the first output
provided, shown in Figure 1. From the output, we can
see that this file has three simulations. The first
simulation has one structured zone that contains one
million cells. The second simulation has four
unstructured zones with each zone containing 250,000
cells (hence, this file has been decomposed into four
zones to run on four processors). The last simulation
contains two unstructured zones with each zone
containing 500,000 cells (hence, this file has been
decomposed into four zones to run on two processors).
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Deleting a Simulation (DTF -del_sim
option):
Now that we know how to view the general information
about the DTF file, we could delete a simulation from
the file. To delete a simulation from a DTF file, you
will need to use the following command:
DTF -del_sim modelname.DTF [sim_number]
In this example, I want to delete simulation number
2. To do so, execute the following command:
DTF -del_sim test.DTF 2
You will be prompted to answer "Are you sure?". Type
'y' for yes to delete the simulation or 'n' for no to
exit the command. If you type 'y', then you should see
the following:
Figure 2. Output from the DTF -del_sim
command
From the output, you can see that there are now two
simulations in the DTF file and they are numbered from
1 to 2. We can now execute the DTF -i command again to
view the information in the DTF file now that we have
deleted a simulation.
Figure 3. DTF -i command now shows 2 simulations
in the DTF file
The file now has two simulations in it. To delete
another simulation, just execute the DTF -del_sim
command again and specify the simulation number for the
simulation to be deleted.
The DTF -i and -del_sim
options can be very useful when you need to view
information about a DTF file or delete a simulation
from a DTF file. The -del_sim command is
probably most useful when running parallel
computations, while the -i option is
useful for viewing general information about a DTF
file. Try using these options in the future if the
need arises.
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We welcome your discussion and comments about this
note on the ESI CFD
Community forum. A topic has already been started
and you can
find it here. [Access available only to
customers under a current support contract.]
William Kuykendall
Applications Engineer
ESI CFD Customer Support
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Happy Holidays from ESI Group! From everyone here at ESI Group, we would like to
wish you and your family a safe and happy holiday
season.
How to Compare the Model Setup Between Two DTF Files Have you ever wanted to find the differences between
two DTF files? If you have, then you will probably be
interested in a DTF utility included in your ESI
Software installation.
The utility is called
dtf_diff and can be found in your
UTILS_2009.0/bin directory.
CFD-ACE+ V2011.0 Physics Compatibility Matrix
Have you ever wondered what would happen if you turned on all of the physics and features of the
CFD-ACE+ solver? Or if it is even possible? More likely, you have run into a new modeling task that
requires you to use modules and features together that you have never used in those combinations
before, and would thus like to know if they are compatible with each other.
Box Zoom Feature
Did you know you can zoom in on any area of a model just by creating a box in the graphics window?
This feature is very user friendly and provides quick access for zoom-in capability.
Always Make Sure You Have a Good Mesh Quality
The mesh has a great influence on the solver convergence and solution of every CFD Simulation. The user is strongly advised to check the quality of a numerical mesh.
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