Simcenter STAR-CCM+ How many inner iterations did my time step use?

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In this article you will find an answer for the question how to monitor and plot number of inner iteration during transient run with advanced/intelligent stopping criteria in Simcenter STAR-CCM+.


When running a transient simulation, it is often beneficial to use stopping criteria based on one or several physical quantities, such as maximum pressure or volume average velocity. Just using a fixed number of steps will likely lead to either using too many inner iterations or non-convergence within a time step.

In this example, we will advance in timestep when stopping criteria from point 1. or 2. (below) are fulfilled:
  1. Continuity Criterion AND Minimum Inner Iterations AND Volume Average Velocity Monitor Criterion,
  2. Maximum Inner Iterations.

Quite the strong stopping criteria!

Looking at the residuals we can see that the simulation seems to use about 10-40 iterations/timestep.
You can of course manually check how many iterations were used at each timestep but how do we plot this?

We will need to create:
  1. A new Expression Report of: ${Iteration}, with a monitor triggered at each timestep,
  2. A new Statistics Report of the Monitor from point 1 that will sum up the iterations from this and the previous timestep (Last N Samples = 2),
  3. A new Expression Report of: 2*report from point 1 minus report from point 2,
  4. Create Monitor and Plot of report from point 3.
The fastest way however, would be to just download and run the attached java-macro. For reference see attached .sim file as well.

KB Article ID# KB000042064_EN_US



Associated Components

Design Manager Electronics Cooling In-Cylinder (STAR-ICE) Job Manager Simcenter STAR-CCM+