Setting Up Automatic Inner Iterations

You can optimize the computational time of your VOF simulation by automatically adjusting the number of inner iterations per time-step. You achieve this optimization by creating a stopping criterion for the inner iterations of the activated solvers based on the relative mass error rate. Activating this stopping criterion lets Simcenter STAR-CCM+ automatically determine the number of inner iterations to reach a minimum accuracy limit for mass conservation.

Before you begin, select the mass error rate model.
To set up automatic inner iterations:
  1. Right-click the Reports node and select New Report > Maximum.
  2. Select the newly created Maximum 1 node and set Scalar Field Function to Relative Mass Error Rate > Relative Mass Error Rate of [Phase].
  3. Right-click the Maximum 1 node and select Create Monitor from Report.
  4. Select the Monitors > Maximum 1 Monitor node and set Trigger to Iteration.
  5. Right-click the Stopping Criteria node and select Create New Criterion > From Monitor... > Maximum 1 Monitor.
  6. Right-click the Stopping Criteria node and select Create New Criterion > Minimum Inner Iterations.
  7. Edit the Stopping Criteria node and set the following the properties:
    Node Property Setting
    Maximum 1 Monitor Criterion Logical Rule And
    Minimum Limit Minimum Value Provide a minimum limit for the relative mass error rate. You choose the minimum limit, for example, by considering the variation in weight of a casted part. If the weight varies, for instance, by 3% and the total physical simulation time is, for example, 8 s, a value like 3%/8s = 0.375 %/s is appropriate for this example.
    Minimum Inner Iterations Minimum Inner Iterations Specify the minimum number of inner iterations for each unsteady time-step.
    Logical Rule And