TUT: Added example showing use of functionObject result lookup from a Function1

tutorials/incompressible/simpleFoam/simpleCar/README

+# 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;
+    }
+```

tutorials/incompressible/simpleFoam/simpleCar/system/controlDict

@@ -48,6 +48,7 @@ functions
 {
     #include "forceCoeffs"
     #include "fieldAverage"
+    #include "referencePressure"
     #include "runTimeControls"
 }
 

tutorials/incompressible/simpleFoam/simpleCar/system/referencePressure

+/*--------------------------------*- C++ -*----------------------------------*\
+| =========                 |                                                 |
+| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
+|  \\    /   O peration     | Version:  v2106                                 |
+|   \\  /    A nd           | Website:  www.openfoam.com                      |
+|    \\/     M anipulation  |                                                 |
+\*---------------------------------------------------------------------------*/
+
+sample1
+{
+    type            sets;
+    libs            (sampling);
+    interpolationScheme cellPointFace;
+    setFormat       raw;
+    fields          ( p );
+
+    sets
+    (
+        cloud
+        {
+            type    cloud;
+            axis    xyz;
+            points
+            (
+                (1 0.2 0.05)
+                (1 0.4 0.05)
+                (1 0.6 0.05)
+                (1 0.8 0.05)
+                (1 1.0 0.05)
+            );
+        }
+    );
+}
+
+average1
+{
+    type            valueAverage;
+    libs            (fieldFunctionObjects);
+    writeControl    writeTime;
+    functionObject  sample1;
+    fields          (average(p));
+}
+
+reference1
+{
+    type            reference;
+    libs            (fieldFunctionObjects);
+    writeControl    writeTime;
+    field           p;
+    refValue        functionObjectValue;
+    functionObject  average1;
+    functionObjectResult average(p)Mean;
+}
+
+reference2
+{
+    type            reference;
+    libs            (fieldFunctionObjects);
+    writeControl    writeTime;
+    field           p;
+    refValue        sample;
+    position        (1 0.2 0.05);
+}
+
+
+// ************************************************************************* //