Simcenter FLOEFD FLOEFD: How to set an OR-type finishing condition in a transient calculation

In the "Finishing" tab from the "Calculation control options" we can define the condition or conditions that will be considered to stop the calculation, such as goals convergence, physical time, or number of iterations. If we want to stop the solver when one single goal reaches a specific value, then we have to activate the "Goal Convergence" finish condition. For the "Criterion to stop", “one satisfied” doesn’t mean that the simulation will stop if only one goal criteria is satisfied, it means that the goals convergence is the only criterion.

Let's consider a case when we create three different volume goals to monitor the maximum temperature of three different components. If we want to stop the calculation when only one of these goals reaches a specific value, we can proceed with the following procedure:

• Go to the FLOEFD parameters and define the maximum temperature allowed for the components:

• Create the goals to monitor the temperature of the different components.

• Create the “FinishCond” parameter, set the type to “Formula definition” and in the definition, type a formula similar to this one using the parameters and goals that were already created:

IF((({VG T1 Max}>{T1_LimitTemp})OR({VG T2 Max}>{T2_LimitTemp})OR({VG T3 Max}>{T3_LimitTemp}));2;0)

This formula means that the “FinishCond” parameter will change from 0 to 2 if one of the created goals values is higher than the defined limit temperature value. For the formula creation you can use the “Parameter” and “Goal” buttons to add the goals and parameters to the formula definition:

• Create the “Finish” equation goal, for the expression set the goal value equal to the “FinishCond” parameter (“Finish” goal = “FinishCond” parameter):

• Finally, in the “Finishing tab”, select the “Finish” goal as the only goal for the convergence criteria. For the criteria set “> absolute value”-> 1. This means that when the “FinishCond” parameter changes from 0 to 2 if one “OR” condition is satisfied (one temperature goes higher than the limit temperature), the goals criteria will be also satisfied.

• Here is an example using the values from this article; the solver stopped when the “VG T3 Max” goal value is higher than the “T3_LimitTemp” value (297 K), even when the other goals value ("VG T1 Max" and "VG T3 Max") are lower than the limit temperature specified, 295 K and 296 K, respectively.