# Tutorial case: simpleCar
Provides example of using the function objects:
- forceCoeffs
- fieldAverage
- reference
- runTimeControls
The case automatically terminates according to the runTimeControls:
- The first condition monitors the average drag coefficient, derived from a
combination of the forceCoeffs and valueAverage function objects. When the
average stabilises to a tolerance of 1e-3 it sets the trigger 1 index
```
runTimeControl1
{
type runTimeControl;
libs (utilityFunctionObjects);
conditions
{
condition1
{
type average;
functionObject forceCoeffs1;
fields (Cd);
tolerance 1e-3;
window 20;
windowType exact;
}
}
satisfiedAction setTrigger;
trigger 1;
}
```
- This starts the second condition, which instructs the code to terminate
after a further 100 time steps.
```
runTimeControl2
{
type runTimeControl;
libs (utilityFunctionObjects);
controlMode trigger;
triggerStart 1;
conditions
{
condition1
{
type maxDuration;
duration 100;
}
}
satisfiedAction end;
}
```
The `reference` function object provides an additional example where:
- the average of the sample object values are averaged in time:
```
average1
{
type valueAverage;
libs (fieldFunctionObjects);
writeControl writeTime;
// Average the result of the `sample1` function object, where the
// result is given by the name `average(p)`
functionObject sample1;
fields (average(p));
}
```
- this value is used by the `reference` function object, where the refValue
is a Function1 entry:
```
reference1
{
type reference;
libs (fieldFunctionObjects);
writeControl writeTime;
field p;
// Set the refValue according to the result of the `average1` function
// object, where the result is given by the name `average(p)Mean`
refValue functionObjectValue;
functionObject average1;
functionObjectResult average(p)Mean;
}
```
