# Asymptotic stopping criterion is not working

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 January 25, 2013, 07:05 Asymptotic stopping criterion is not working #1 New Member   rob roy Join Date: Jun 2011 Posts: 3 Rep Power: 14 Hello, I have a problem with the user defined asymptotic stopping criterion in StarCCM+ 7.06: I'm calculating the resistance of a ship using free surface with VOF and DFBI (6DOF). I created a stopping criterion from a force monitor. The plot of the force monitor is decreasingly oscillating. Using the asymptotic stopping criterion for the outer iterations I want to stop the calculations ones the oscillation is within a certain limit for a certain time. In the stopping criterion I set number of samples to 10 and |Max-Min| to the desired oscillation limit. My problem is that the criterion is never fulfilled, no matter how high I set the oscillation limit. example: over a period of 10 timesteps my plotted force changes about 1N. So I would expect a criterion with 10samples and |Max-Min|=2N to immediately stop the calculation but that doesn't happen (the "criterion satisfied" checkbox is "false" all the time). The Minimum and Maximum criteria work fine by the way! Did anybody encounter the same problems? Might there be a bug in StarCCM+? Arsham likes this.

 January 27, 2013, 10:13 #2 Member   Ryan Coe Join Date: Jun 2010 Location: Albuquerque, NM Posts: 98 Rep Power: 15 I encountered this same issue a while ago. Like you I was confounded. When I finally talked to a CD-adapco rep., he explained that the asymptotic limit is simply controlling the inner iterations (this makes sense when you look at the node structure in the GUI). When the limit is met, the simulation advances to the next time-step. I agree that it would be nice to have an asymptotic limit to end the unsteady simulation. You could try to write a field function or macro like: if: (asymptotic condition met) then: set TimeLimit = (CurrentTimeLevel - 1s) __________________ Ryan

 January 28, 2013, 08:25 #3 New Member   rob roy Join Date: Jun 2011 Posts: 3 Rep Power: 14 Thanks! I will try that.