Hi all,

I would like to ask the function of "restart current run" in CFX5.5 Solver.

For my situation, sometimes there is a electricity problem in my office, so it will terminate my running in the solver before the runnung finished. There's only .out file in my directory and no corresponding .res file.

So, can I use the "restart current run" for the unfinished running? If yes, how can I activate that function (because the function is in grey)? Anyone can help me please? Thank you in advance.

Regards, Sara

Hi Sara,

As I understand it:

The "restart run" command is just a shortcut for defining a new run with the same .def file as the one you are viewing using the latest .res file as initial values file. If there is no .res file, CFX cannot 'restart' the run so the option will be grayed out.

Your real problem seems to be that the intermediary calculation results are not saved before your machine drops out.

You will probably want to check out the solver backup frequency option in Build under Solver Control / Options. If you set it to a non-zero value, intermediary dat will be saved every so many iterations & you can restart from that data later on (Please read the corresponding section in CFX help for details).

good luck,

Bouke

Hi Bouke,

I've just experienced the same problem again before getting your advice...! So, really thanks for your response and advice. Hope it helps me to fix this "FREQUENT" problem! Hahaa...Kidding!^^

Thanks again.

Sara

Question for you both, if you set the out put frequency to a non zero then you will get multiple result files ? Once a run is finished can you then just delete these (as space will become an issue) or do you have to keep them ? I've found in CFD Post that you need to keep all transient result files labeled .trn, even if you are not interested in the majority of the results. If you don't keep all the files then Post will not allow you to view the results. Has anyone else found this ?

Bob,

You indeed get multiple result files. It would be a nice feature if you could choose to generate only one and overwrite it, so save space / allow more frequent backups as a protection against e.g. power failures, but I don't think this is currently possible.

For transient simulations, you do not specify the backup frequency but create transient result files instead, but this is more or less the same thing, provided you use full result files (containing all flow data) and not minimal ones (containing data only for selected variables).

For restarting a crashed simulation you need to keep only the last of these files. (Although in transient cases you probably want to keep several anyway for post-processing).

I have not experienced your problem with trn files in CFX Post. I did have some trouble using Timestep selector (it looks in a wrong directory when loading trn files) so I use "Load results" to read in trn files. This may be tedious if you need to look at many different time steps, but I guess it should always be possible (provided the trn file is not corrupted). I have not tried this with minimal result files, however.

Hope this helps,

Bouke

Try the expert parameter "delete backup files".

Hi,

There is one more question that if i'm running a transient simulation and there's a sudden power failure, how can I do? There're some .trn files but no .res file in the directory. So, can I restart from where it was stopped? And it seems that we can't set the "solver backup frequency" for the transient simulation. So, any suggestions to me for the sudden power failure when running a transient simulation? Thanks!

Regards, Sara

Hi Sara, I think you can specify in the transient result output section of Build, to specify either a full results output or a minimal output. The full output will allow you to restart from it. However this will take up more disk space as there is more information in the file than in the minimal results file. Bob

Yes, the transient results files are stored in a subdirectory from your working directory and should have a similar name to the run you are doing. If you COPY the last (full) transient results file saved from the sub-directory and put it in you working directory you can use this as your restart file. I would rename it to something more useful and give it a .res extension. I would probably also get your electrics looked at as well