Learning Forum

[Scott Ormiston]

In Fluent, I would like to use a monitor point value (e.g., mass flow rate at an outlet) as an asymptotic steady-state convergence check (like in STAR-CCM+). I would like to check the percentage change of the monitored quantity over a number of iterations and stop iterating when it meets a certain criterion. 

How can this be done in Fluent?

[SRP]

Hi,

You can create an report definition and use the convergence condition.

For more details, you can check user's guide: 36.16. Convergence Conditions (ansys.com)

Thank you

[Scott Ormiston]

Thank you for the pointer to the manual.

Is there a way of doing the convergence check without normalization?

[Scott Ormiston]

As a follow-up: If the actual value of the report cannot be used as a convergence check, an idea we had was to do the check of the asymptotic

convergence in a UDF and then write a STOP file to the directory when the convergence is met.  Is there a better way to declare convergence using a UDF? The STOP file closes the GUI, which is not desirable. Can convergence be checked on a UDMI value?

[SRP]

Hi,

User defined report definitions can also be used in the Convergence Conditions.User defined report definition functions are defined with the Define_Report_Definition_Fn macro, which takes the function name as the argument. The function must return a real value. Once written, it should be compiled and loaded the same way as other user-defined functions. With the user defined report definition function written, you must hook this function to the user defined report definition.

For more details on this macro, you can check here: 40.2. Monitoring and Reporting Solution Data (ansys.com)

[Scott Ormiston]

Thank you.