Setting Solver Parameters and Stopping Criteria

To make sure that a reasonable solution is obtained, apply linear ramps to the key under-relaxation parameters and also tighten the AMG linear solver convergence tolerance.

To set the solver parameters and the stopping criteria:

  1. Select the Solvers > Segregated Flow > Velocity > Under-Relaxation Factor Ramp node and set Ramp Method to Linear Ramp.
  2. Beneath the Under-Relaxation Factor Ramp node, select the Linear Ramp node and set the following properties:
    Property Value
    Start Iteration 1
    End Iteration 200
    Initial Value 0.5
  3. Similarly, select the Segregated Flow > Pressure > Under-Relaxation Factor Ramp node and set Ramp Method to Linear Ramp
  4. Beneath the Under-Relaxation Factor Ramp node, select the Linear Ramp node and set the following properties:
    Property Value
    Start Iteration 1
    End Iteration 200
    Initial Value 0.2
  5. Select the Pressure > AMG Linear Solver node and change the Convergence Tolerance to 0.05.
The simulation runs for 600 iterations. This number can be specified using a stopping criterion, as follows:
  1. Select the Stopping Criteria > Maximum Steps node and change the Maximum Steps to 600.
  2. Save the simulation.