Learning Forum

[Mehdi Salakhi]

Hello,

I have been trying to couple my Rocky setup with my Fluent case where Magnetohydrodynamics (MHD) model is on, but there is an error while reading the journal file of the Fluent. I have attached a screenshot of this. Rocky recognized the UDS and UDMs of Fleunt's case, but Fluent can't be run. I'd appreciate any bit of help here. I have added the MHD module using text commands in Fluent.

[Rob]

I suspect the addon module for MHD is trying to overwrite or otherwise is in conflict with the Rocky links. Both use a mix of UDF, UDS and UDM to store & pass data so I wonder if there's a clash somewhere in the set up. How are you passing the MHD fields to Rocky to also alter the particle motion? 

[Mehdi Salakhi]

Thank you, Rob, for your comment.

So, initially, I added the MHD module through the text command "Define/models/addon-module", and then saved my Fluent case. In Rocky, I loaded the Fluent case, and after that, everything is automated. I checked the Rocky setup, and it seems that it recognized the MHD field as attached below. However, I'm not using any MHD fields in particle motion. As a first step, I just wanted to check the coupling between Rocky and Fluent with MHD fields.

 

 

 

[Rob]

That should work. I'm waiting to hear back from my counterparts in the Rocky team, that may not be until next week. Post a reminder in here Tuesday late afternoon if I've not posted by then. 

[Rob]

 

We think it’s a data passing issue, Rocky needs to do something that it can’t as Fluent’s addon modules behave slightly differently. We’ll investigate and try with 23R2 and beyond. 

 

[Mehdi Salakhi]

Hi Rob,

Thank you for looking into this issue, as it is critical for my work. I'm hopeful that we can find a solution soon. I wanted to bring to your attention that I'm encountering the same problem with Rocky when I set my Fluent case with a Chemkin reaction mechanism file, which is an external UDF file. I'm not sure if this information is helpful, but I thought it might be worth mentioning. Technically, I have to add all the reactions manually. In this case, I can run Rocky with Fluent.

Additionally, I was curious whether it might be possible to obtain a beta version of 23R2. I'm concerned about falling behind in my research and am eager to try out any potential fixes as soon as possible. Thank you again for your help.

[Rob]

We don't issue beta versions very often, so you're better off waiting for the formal release: even more so given the "main" Ansys package and Rocky may not release at exactly the same time. I also don't know whether the fix will be applied by then. External UDFs should work, but given it's a reaction there may be an unexpected conflict somewhere. I'll remind my counterpart in the Rocky team.