ENH: portable scoping char for fieldCoordinateSystemTransform (fixes #1675)

- replace ':' scoping with IOobject::scopedName(), which automatically
  uses '_' for Windows compilations where the ':' is a meta-character
  (drive separator)

- apply similar local change for the momentum function object.

*** This topic will be revisited in the future ***

src/functionObjects/field/fieldCoordinateSystemTransform/fieldCoordinateSystemTransform.C

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2017-2019 OpenCFD Ltd.
+    Copyright (C) 2017-2020 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -80,7 +80,7 @@ Foam::functionObjects::fieldCoordinateSystemTransform::transformFieldName
     const word& fieldName
 ) const
 {
-    return fieldName + ":Transformed";
+    return IOobject::scopedName(fieldName, "Transformed");
 }
 
 
@@ -90,7 +90,7 @@ Foam::functionObjects::fieldCoordinateSystemTransform::srotTensor() const
     typedef surfaceTensorField FieldType;
     typedef surfaceTensorField::Boundary BoundaryType;
 
-    if (!rotTensorSurface_.valid())
+    if (!rotTensorSurface_)
     {
         tensorField rotations(csysPtr_->R(mesh_.faceCentres()));
 
@@ -135,7 +135,7 @@ Foam::functionObjects::fieldCoordinateSystemTransform::vrotTensor() const
     typedef volTensorField FieldType;
     typedef volTensorField::Boundary BoundaryType;
 
-    if (!rotTensorVolume_.valid())
+    if (!rotTensorVolume_)
     {
         tensorField rotations(csysPtr_->R(mesh_.cellCentres()));
 

src/functionObjects/field/momentum/momentum.H

@@ -135,7 +135,7 @@ SourceFiles
 namespace Foam
 {
 
-// Forward declarations
+// Forward Declarations
 class dimensionSet;
 
 namespace functionObjects
@@ -225,6 +225,15 @@ protected:
         //- Write momentum data
         void writeValues(Ostream& os);
 
+    // Protected Member Functions
+
+        //- Return a scoped name
+        //  TODO - revisit issue #1675
+        word scopedName(const word& base) const
+        {
+            return IOobject::scopedName(this->name(), base);
+        }
+
 
 public: