Setting Solver Parameters and Stopping Criteria

Training Guide > Rotating System Tutorials > Rigid Body Motion Tutorial > Setting Solver Parameters and Stopping Criteria

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Setting Solver Parameters and Stopping Criteria

As the analysis is now unsteady, we need to specify the time-step size.

Select the Solvers > Implicit Unsteady node

In the Properties window, change the Time-Step to 1.04167e-4 s. For the rotation speed specified (2000 rpm), this means that one full revolution will comprise 288 time-steps.

The calculation will be run for 0.03 s, i.e. one full revolution. This should be sufficient for the solution cycle (which will repeat every 1/12 of a revolution due to there being 12 identical, equally-spaced blades) to be resolved to a reasonable degree of accuracy. The run length can be specified using a stopping criterion as follows:

Select the Stopping Criteria > Maximum Physical Time node

In the Properties window, change the Max Physical Time property to 0.03 s

The number of inner iterations per time-step is set to 20 by default. For many cases, this value is far too large and using a lower value can significantly reduce the computing time.

Select the Maximum Inner Iterations node and change the Max Inner Iterations property to 5

The Maximum Steps stopping criterion is set to 1000 by default. Since we will be running the analysis for 288 time-steps at 5 iterations per time-step, this stopping criterion should be removed.

Select the Maximum Steps node and deselect Enabled in the Properties window

Save the simulation

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