CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > CFX

Hard drive storage and .cfx vs .def files

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 13, 2011, 10:09
Default Hard drive storage and .cfx vs .def files
  #1
New Member
 
Join Date: Jan 2011
Posts: 21
Rep Power: 15
audrey is on a distinguished road
Hi everyone,

This might be a silly question, but I couldn't find a clear answer, either in the manuals or the forums, so I thought I'd just ask.

Is there any important difference between the information contained in .cfx and .def files? I've been struggling with limited hard drive storage space (I know about all obvious solutions, here, like buying an external hard drive, but school regulations make these impractical - I would have to buy backed up storage on the university server which is on the expensive end for a project with no budget...)

To make a long story short, I'm trying to stretch my hard disk space and I noticed that .cfx and .def files can get pretty large. I've got loads of them, and I like to keep them in case I want to go back to a previous simulation setup, but I was wondering if there was a good reason to keep both .cfx and .def files for previously run simulations, or whether keeping just one of them would give me all the info I need. (I understand that in theory, all the info is printed in the .out file, but who wants to start from stratch every time...)

Thanks,
Audrey
audrey is offline   Reply With Quote

Old   September 13, 2011, 11:01
Default
  #2
Senior Member
 
Join Date: Apr 2009
Posts: 531
Rep Power: 21
stumpy is on a distinguished road
I usually just keep the .def files. You can open a .def file in CFX-Pre then hit save to recover the .cfx file. The .def file only contains the info needed for the current run, so in some cases the .cfx file can contain additional information (e.g. materials and other library data that have been defined but not used), but this isn't usually a concern.
stumpy is offline   Reply With Quote

Old   September 13, 2011, 11:05
Default
  #3
New Member
 
Join Date: Jan 2011
Posts: 21
Rep Power: 15
audrey is on a distinguished road
Thanks! That makes sense. The extra stuff that has been defined but not used is actually more of a problem than a solution for me, because I keep realising that I forgot to update an expression or the properties of a material... I think I'll adopt the same strategy and only keep .def files. (I'll probably keep .cfx files for some of the most recent runs, just in case)
audrey is offline   Reply With Quote

Old   September 15, 2011, 22:39
Default
  #4
Senior Member
 
Bruno
Join Date: Mar 2009
Location: Brazil
Posts: 277
Rep Power: 21
brunoc is on a distinguished road
I think the only time a .cfx file is better then a def file is when you're working with a multiconfiguration setup and you have only one mesh (say, if you're setting a multiconfiguration run to start with a steady state simulation and then go transient). In that case the mesh is the same, and the .cfx file will only store one instance of it. The def (or mdef, for multiconfiguration definitions) file won't be a single file, but a folder filled with the different configrations generated.

An if your really have to save space, delete the res and keep the out file, so at least you know what you'll have to do to get to the same result.
brunoc is offline   Reply With Quote

Old   September 16, 2011, 01:34
Default
  #5
Member
 
D
Join Date: Nov 2010
Posts: 50
Rep Power: 15
bhatiadinesh is on a distinguished road
One other instance where a CFX file is better than a def file is when you have multiple meshes which you have imported individully imported in CFX and have joined them using interfaces. In such a case if you need to replace only a single mesh file, then CFX file is your easy way out, coz in de4f you cannot perform this as .def file will show a single mesh.

-Dinesh
bhatiadinesh is offline   Reply With Quote

Old   September 16, 2011, 07:19
Default
  #6
New Member
 
Join Date: Jan 2011
Posts: 21
Rep Power: 15
audrey is on a distinguished road
Thanks, that's good to know. For now, I'm sticking to steady state simulations with a single mesh, so I think it's ok to keep only .def files. I've been keeping most .res files, but if I run out of space too quickly, I might start deleting the simulations that didn,t converge - I've got LOADS of those.......
audrey is offline   Reply With Quote

Reply

Tags
.cfx, .def, storage


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On



All times are GMT -4. The time now is 12:36.