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-   -   Fluent exceeding Solution Limits on faces (http://www.cfd-online.com/Forums/fluent/104443-fluent-exceeding-solution-limits-faces.html)

bawfuls July 9, 2012 20:44

Fluent exceeding Solution Limits on faces
 
I am using Fluent with a compiled UDF to provide some boundary conditions, specifically a wall heat flux (but the UDF should be irrelevant to this particular issue). I have set the minimum and maximum temperatures in Fluent to 200 K and 2200 K, respectively via the Solution Limits box under Solution Controls. Despite this, when I use the UDF command F_T(face,f_thread) to query the temperature on a boundary face, Fluent often returns a value well outside these temperature limits (including very negative values). Do the Solution Limits specified under Solution Controls not apply to faces? How can I force Fluent to limit ALL temperatures (including faces) to these limits?

flotus1 July 10, 2012 00:20

Maybe you could use a bounded scheme (like first order upwind) for the computation of the Energy equation.

bawfuls July 10, 2012 15:49

Quote:

Originally Posted by flotus1 (Post 370553)
Maybe you could use a bounded scheme (like first order upwind) for the computation of the Energy equation.

I am already using first order upwind for the energy equation in this case, so that doesn't seem to be the issue.

flotus1 July 10, 2012 16:34

You are right, with a first order upwind scheme, over- and undershoots should not appear, especially when the range of the variable is set as a limit for the solver.

I'd be interested in a solution to this problem too.
My current analysis features a melting process in which the liquidus temperature is exceeded before the cell is fully melted.


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