Workbench And HPC Cluster
 

Hi All

Does anyone have experience or information regarding how to use Ansys Workbench, with parameters and do different CFX Computations at a time in the HPC ? Or do I have to write different .def file and do the computations separately, with CFX as standalone ?

Regards

I tried to get RSM up and running once but that did not work reliably.
I ended up creating def files in Workbench and starting the jobs on the cluster via command line.

It is possible, I do solves frequently enough directly on the cluster with Workbench, with and without RSM. Which version are you on and what are your parameters? The configuration of your parameters could dictate workflow.

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Workbench makes this easy. Choose a parameter in CFX pre as a "workbench input parameter", run that case. In CFX post choose an expression as "workbench output parameter". Now you'll have a tab called Parameters. Fill in the table with different values for input parameter and then "update all design points" and you'll solve the new cases. In solve settings you have to choose "one job for every design point" and it will solve them all at once assuming your cluster has the solving resources available.


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Problem with the DesignPointLog.csv
 

Hello,

I use workbench in a cluster, with design point (with inlet and outlet parameters).
To launch a workbench run, the command line is :
Workbench -B -F Workbench.wbpj -R Journal.wbjn

where in the interactive window
Journal.wbjn is obtained by File/Scripting/Record Journal : Journal.wbjn
then click on "Update All Design Point"
then (after few seconds) File/Scripting/ Stop recording

Example : Journal.wbjn
# encoding: utf-8
# Release 18.0
SetScriptVersion(Version="18.0.351")
system1 = GetSystem(Name="CFX 1")
solutionComponent1 = system1.GetComponent(Name="Solution")
solutionComponent1.Update(Force=True)

Click on "Retained" in the parameter tab if you want to save each calculation

In my case, the run is alright, except that the file DesignPointLog.csv doesn't update. This file is a tab where all the outlet parameters should be saved.
Ansys customer service provides no solution, because our cluster is used with "slurm" command.
Is anyone has met this problem and solved it?

Thanks

Hi All

My question is while meshing, I want 3 different mesh sizes and want to generate the mesh and use the same solver setttings / boundary conditions. And in my cluster I submit the job as .def and .ccl file as input file for the cluster. So how does workbench do that ?

You set it up as 3 fluid simulation blocks in workbench.

But I would not do it in workbench, I would use CFX stand-alone and use the command line tools to script it together.

Either way works fine, use whatever you are familiar with.

Hi Glenn

So you mean to do 3 different meshes first and do 3 different .def file and so the simulation separately ? The thing is I want to do it in such a way that you set the 3 different mesh size as parameter and do the simulation and then get the result based on the 3 different mesh sizes

I see. This is very easy in workbench. It can also be done using scripts but would be considerably harder. So workbench would be my first choice for this.

So my question was how can we do it in Workbench. But I cannot open workbench on my cluster , only I can submit some jobs in cluster So am not sure how I can do it.

This is easy using parameters in workbench.

Is there any tutorial that explains this how to generate it in linux machine ? As far as I heard Ansys workbench doesnt support linux and how does it generate different def file for different parameters ? Could you give me a short explanation how to do this. Would be really great.

Also to add up, for example I want to try with different inlet conditions (Velocity, Total Pressure ) with same outlet boundary condition.
And in each Inlet conditions I have different values .
So currently I am using CFX as standalone and generating the .ccl file and .def file and doing the computation. But it would be great if I had something to do with workbench directly and generate the .def file and ccl file and load it to my HPC machine and get the simulations done.

Workbench is supported in Linux.

Workbench does all the new meshes, def files and everything else internally when you do it through parameters. If you do not know about parameters in Workbench then you better learn about them - it is quite a powerful system.

The best way to learn about parameters is to look at the workbench tutorials on the ANSYS Customer website. Not the CFX tutorials, parameters will be covered in workbench.

But does it directly on the cluster and it does the simulation too ? I have used it locally in windows , but for huge jobs am bit scared or am not aware how I can submit it as a job in cluster. I just have the pbs script for CFX and it needs the input .def and .ccl file. And I guess workbench will need something similar right ? But anyways I will have a look in the Workbench Manuel.

did you sort this?? I need to do something similar i need a def file to submit to cluster but want to run several design points i have set up under parameters in workbench

The ANSYS documentation describes how to set workbench and CFX up for cluster operation. Then you can run it easily on the cluster.

Do you have this link? I'm trying to submit a workbench and a journal file to a cluster that uses slurm and bash code and I need some guidance.
Thanks in advance

If you use CFX outside Workbench, you can easily create a batch file from a command line that can do multiple reuns when you are asleep.
With different ccl-text files, you can read different settings into a single definition file and do various studies.
Is this somehting that could be of help?

Hi Gert-Jan,
Thanks for the reply!
Yes this could be of help.
Would it work for fluent also if I'm running it through workbench?