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Turn on data sampling in batch process

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Old   October 5, 2018, 11:34
Default Turn on data sampling in batch process
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Hi guys. I am simulating on a cluster and want to turn on data sampling via a batch script. For this i am using the command /solve/set/data-sampling yes 1 yes yes yes. Is this correct?
I can only simulate for a certain amount of time on the cluster until I have to restart my simulation from the previously obtained solution. What do I have to specify in my batch script to continue averaging? Do I have to delete the command or should I keep it in the batch script? If i keep it, does Fluent restart the averaging process and deletes the old averaged data?
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Old   October 5, 2018, 13:18
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It's probably easier to setup interactively because once it is activated, you do not need to include it in the batch script.


Usually the inputs you need to provide prompts for are:


Code:
Data Sampling for Time Staatistics? [y/n]
Sampling interval [#]
Collect statistics for flow shear stresses? []
Collect statistics for flow heat fluxes? []
Collect wall statistics? []
The first yes enables data sampling. The number is the sampling interval. These two you obviously need. The following three are optional. If you run other models there might be additional prompts that you need to provide more yes/no for. For example if you have any custom field functions declared the next prompts would be:


Code:
Collect statistics for Custom Field Functions?
Unsteady statistics for custom-function-0?

In this case there would be two more yes/no's needed.


You should definitely get into the habit of testing these interactive (in GUI or without a GUI) because it will change depending on your model and not always the same command string will work.


Once it is enabled, it stays enabled. You only need to do this once and then save the case; unless you want to change the sampling interval or turn it off. So you do not need to include it in the batch script.



The statistics are always saved with the .dat file and are never cleared. If you want to clear the statistics at some point then you use:


Code:
/solve/initialize/init-flow-statistics
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Old   October 6, 2018, 08:11
Default using the command in the batch script
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Thank you very much for this explanation! It made a lot of things clear!

The thing is i only can start my simulation on the cluster via batch script. I don't have access to the Fluent running in the background. I have to activate data-sampling in the batch script because I want to start sampling after let's say 10000 time steps. BUT, after another 10000 time steps i have to restart my simulation because of cluster time limitations again with the batch script and i want to sample my data over a period of 20000 time steps. Do i have to keep the command in the batch script for the second "averaging run" or can I / do I have to delete it? According to your explanation I can delete it. Once it is turned on it won't turn off except I am specifically tell Fluent to do so, right? Furthermore, keeping it in the batch script for the second averaging run (timesteps 20000 - 30000) won't delete the previously sampled data from timesteps 10000 - 20000, it will just continue the sampling, right? Basically, keeping it in the batch script for the second averaging run won't have any effect on the simulation or the sampled data, right?
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Old   October 10, 2018, 05:47
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Any idea? Someone?
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