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Simulation CFD

*Expert Elite*
440 Posts
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Registered: ‎10-02-2012
Accepted Solution

Hidden flags

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10-04-2013 02:46 AM

I am very intrigued with some of the flags listed in SimCFD 2014, but unfortunately I don't see any explanation in offline documentation. 


Some of them are:

1) coupled_solver_flag: Does this mean 2014 does have coupled solver formulation for continuity/momentum equation? It will be interesting if this is the case since it will speed up the convergence as compared to current slow SIMPLE based seggregated solver. On enabling it for simple turbulent flow, it gave me the error "Solver exited unexpectedly"

2) ke-scal_wallfunc: Does 2014 have scalable wall function? I think this will cushion against the wrong results due to unnecessary refined prism mesh at walls 

3) momentum_resolution: What does this do?

4) no_difu_tensors: If resistance surfaces are used, does enabling/disabling this have any effect at all? I presume the pressure drop for surface resistances are calculated as scalar quantities, so not sure if tensor definitions would influence that...


Additionally, there are some flags that are not even listed in flag manager but are documented in knowledge base


1) automesh resolution_factor 

2) automesh minimum_points


Is there any document that explains all the other flags missing from the help documentation? Even any internal document will do, as long as it explains the functionality. I would love to tweak these flags and arrive at the best setting for our application.





Product Support
662 Posts
231 Kudos
Registered: ‎08-24-2011

Re: Hidden flags

10-04-2013 08:50 AM in reply to: OmkarJ

Hi OJ,


Good questions as always!


1) coupled_solver_flag: Developer only flag, this code wasn't actually finished or tested throughly

2) ke-scal_wallfunc: Testing in 2014 code, but also not finished yet.

3) momentum_resolution: Never used this one myself

4) no_difu_tensors: Added in 2014 and should have no effect on surface resistances.


automesh resolution_factor & automesh minimum_points: These allow you to change the advanced mesh options in the UI.  Not really used often.


The best we have for you it to open up the flag manager and read throught the various descriptions.  All of them have a simple description some with more details than others.


Just because I said it is a developer only flag doesn't mean you can't use it, just don't tell us it isn't working :smileywink:

Royce Abel
*Expert Elite*
440 Posts
107 Kudos
Registered: ‎10-02-2012

Re: Hidden flags

10-07-2013 12:55 AM in reply to: Royce_adsk

Thanks. Some of the flags do not have enough description in the flag manager and they are absent in the doco, hence the post :smileyhappy:


The coupled solver seems a very interesting development, in fact, I had posted this idea on the Idea Station. A CFD solver needs a coupled algorithm to be called complete. 


Look forward to the development...