Uabs (for postprocessing) only constructed when needed.

tutorials/simpleSRFFoam/simpleSRFFoam/createFields.H

@@ -26,22 +26,6 @@
         mesh
     );
 
-    // Create absolute velocity field (post-processing only)
-    // Will be updated before first use, so can be initialised by Urel
-    Info<< "Creating field Uabs\n" << endl;
-    volVectorField Uabs
-    (
-        IOobject
-        (
-            "Uabs",
-            runTime.timeName(),
-            mesh,
-            IOobject::NO_READ,
-            IOobject::AUTO_WRITE
-        ),
-        Urel
-    );
-
     Info<< "Reading/calculating face flux field phi\n" << endl;
     surfaceScalarField phi
     (

tutorials/simpleSRFFoam/simpleSRFFoam/simpleSRFFoam.C

@@ -112,9 +112,24 @@ int main(int argc, char *argv[])
 
         turbulence->correct();
 
-        Uabs = Urel + SRF->U();
+
+        if (runTime.outputTime())
+        {
+            volVectorField Uabs
+            (
+                IOobject
+                (
+                    "Uabs",
+                    runTime.timeName(),
+                    mesh,
+                    IOobject::NO_READ,
+                    IOobject::AUTO_WRITE
+                ),
+                Urel + SRF->U()
+            );
 
             runTime.write();
+        }
 
         Info<< "ExecutionTime = " << runTime.elapsedCpuTime() << " s"
             << "  ClockTime = " << runTime.elapsedClockTime() << " s"