Minor cleaning up of cfdemPostproc.

applications/utilities/cfdemPostproc/cfdemPostproc.C

@@ -109,6 +109,7 @@ int main(int argc, char *argv[])
 
         particleCloud.voidFractionM().setvoidFraction(NULL,voidfractions_,particleWeights_,particleVolumes_,particleV_);
 
+        // make sure coupling interval = 1, otherwise update of voidfractionPrev and UsPrev necessary
         voidfraction.ref() = particleCloud.voidFractionM().voidFractionInterp();
         voidfraction.correctBoundaryConditions();
 
@@ -121,6 +122,9 @@ int main(int argc, char *argv[])
             NULL
         );
 
+        Us = particleCloud.averagingM().UsInterp();
+        Us.correctBoundaryConditions();
+
         runTime.write();
 
         particleCloud.IOM().dumpDEMdata();