Flow Simulation has an automatic convergence check feature that will stop the solver when certain criteria is met. This can be controlled by using the Calculation Control Options command located in the Flow Simulation drop down menu (or right-clicking on Input Data in the Flow Simulation feature manager tree).
Flow Simulation Goals
The Flow Simulation developers created “Goals”. Users can define a Goal on any parameter of interest. While the solver is running the user can monitor the goal in the Solver Monitor window. The goal by default is used by the solver to help determine convergence. The user can display the goal history plot while the solver is running. If the goal is relatively flat for many iterations the user can manually stop the solver or just simply wait till the Flow Simulation solver stops on its own.
The convergence for a goal is checked across an “Analysis Interval” determine internally be the Flow Simulation solver. The “Analysis Interval” can be display in the convergence history plot. The “Analysis Interval” is typically between 50 to 100 iterations and the convergence is measured across this span. In the Calculation Control Options command under the Finish tab the user can change certain default settings for convergence.
Grid Convergence
“Grid convergence” is where the user sets up a mesh and runs the analysis. Then the user increases the refinement of the mesh and reruns the analysis comparing the results between the coarser mesh results with the finer mesh results. If the results are relatively the same then the first mesh was acceptable. If the results changed significantly then the user should repeat the process and run a third time with a even finer mesh than the second run. Compare the results between the second and third runs and see if the results changed significantly. The user can use the “Clone of Project” feature to have all the runs saved in different configurations so that the user can easily go back and forth comparing the results. The “Clone of Project” feature can be found in the Flow Simulation drop down menu under Project.