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-   -   extract and export data for each time step (http://www.cfd-online.com/Forums/star-ccm/70713-extract-export-data-each-time-step.html)

thomasbl December 3, 2009 05:08

extract and export data for each time step
 
I want to extract results from a derived plan at each time timestep and export it to one or more files. The data should be read later by MATLAB so I don't think that I can use the auto export function because I can't export it in a format MATLAB can read.

I have no problem exporting the results for a single time step to a .csv file as long as the calculation is not running.

Any suggestions?

dado December 9, 2009 10:50

Try with: File -> Auto Export

Arconis December 14, 2009 13:17

Just got the same problem. Also i don't know how to read ".ccm" format from auto-export.

Subhadeep December 18, 2009 13:10

unsteady simulation data
 
I know of Tecplot360 have an add on package for StarCCM+ unsteady data that could handle this.

I looked at it a bit but could not use it as StarCCM+ was installed on a cluster for me and the Tecplot360 was on a WN based univ desktop comp. To have all the .ccm files read into the system having Tecplot360 was impossible due to data storage.

So if anyone has used this add on successfully let me know so I can at least have the confidence to do it in future if the two are on the same system.

Otherwise its a bit tedious for StarCCM+ unsteady simulation to have a time averaged results like TKE or Reynolds stress. If you look at the field functions for DES, LES these quantities don't exist and one has to write the primary variables out and do the time ensemble averaging outside StarCCM+ environment

dado December 21, 2009 08:29

If you first crate the Report (and the Monitor) with data you want to monitor (choose trigger before you run), then run your case and after that, open the monitors end export it in *.csv format.

thomasbl January 18, 2010 09:25

Quote:

Originally Posted by dado (Post 240641)
If you first crate the Report (and the Monitor) with data you want to monitor (choose trigger before you run), then run your case and after that, open the monitors end export it in *.csv format.

The problem with this method is that I want continious data for a whole plane and not just a single point. And I want the data for each time step.

Until now I have solved the problem by writing a java-script which takes a single time step and exports a table containing only the data I want.

splif June 25, 2010 08:03

LES-Calculation
 
Hello Thomas,

I read that you find a way to write the needed quantities for each time step. I'm really interesting about this tool - i'm doing my diploma thesis - and I will do my simulation with LES.
Wich programm do you use for the analyzing the values? - Matlab? or direct in ccm+?
Do you compare you LES calculation with some exp. data? Are the results good?
I would very hapy if you can give me some advises using LES.
Thank you
Valentin

thomasbl June 26, 2010 10:11

LES-Calculation
 
Since I was not able to use the auto-export function to export data in ascii-format I created a table with the data I was interested in. It is possible to export table data to a .csv file. To be able to export the data for each time step i made a macro which calculates a single time step and the exports the table.
You can make most of the macro directly in CCM+ by using the record button, but you need to make a loop around the commands by yourself afterwards.

I used MATLAB for analysing the data. I only needed a mean velocity and a standard deviation of the velocity.
The values should be compared to some experimental results, but I ended up only using RANS-approaches for the comparison. Therefore I do not have a lot of experience using LES.

flow March 19, 2015 16:58

Hello Thomasbl

I am running a simulation in which I would like to record datas at given positions (line probe) for each time step. You said you wrote a Macro, but I have no clue how to write in Java... Could you share you script to record datas at each time step ?

Thank you very much !

MBdonCFD March 19, 2015 18:35

I don't think you need a script for that. I could be wrong. You should be able to write a table with the results directly to your hard drive for each time step, iteration or whatever. Look at xyz internal tables. I think you just have to select your line probe as the input part then select the scale quantities you want to write to file. Never actually tried it though.

flow March 19, 2015 19:15

MBdonCFD

In deed, there is a way: create a report at each time step of the values of the paramaters I want to store at different line probes. However it creats: a csv file at each time step for each line prob. I have 10 line probs, I am targeting 80 time steps. It means I will end up with 800 files... I wish I could have all the informations stored in one single csv file to make post processing easier !

MBdonCFD March 19, 2015 19:22

I see. Yeah that would be tedious. You could always just write a matlab script to read and sort the data. Probably just as easy to modify a macro recording though.

Good luck.


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