diff --git a/applications/solvers/modules/compressibleVoF/fvModels/VoFSurfaceFilm/VoFPatchTransfer/VoFPatchTransfer.C b/applications/solvers/modules/compressibleVoF/fvModels/VoFSurfaceFilm/VoFPatchTransfer/VoFPatchTransfer.C
index a754e247a4..c6b330cd1b 100644
--- a/applications/solvers/modules/compressibleVoF/fvModels/VoFSurfaceFilm/VoFPatchTransfer/VoFPatchTransfer.C
+++ b/applications/solvers/modules/compressibleVoF/fvModels/VoFSurfaceFilm/VoFPatchTransfer/VoFPatchTransfer.C
@@ -169,8 +169,6 @@ void VoFPatchTransfer::correct
     const volScalarField& alphaVoF = thermo.alpha1();
     const volScalarField& rhoVoF = thermo.thermo1().rho()();
     const volScalarField& heVoF = thermo.thermo1().he();
-    const volScalarField& TVoF = thermo.thermo1().T();
-    const volScalarField CpVoF(thermo.thermo1().Cp());
 
     forAll(patchIDs_, pidi)
     {
@@ -189,36 +187,44 @@ void VoFPatchTransfer::correct
 
         if (primaryPatchi != -1)
         {
-            scalarField deltaCoeffs
+            const scalarField deltaCoeffsVoF
             (
-                film.primaryMesh().boundary()[primaryPatchi].deltaCoeffs()
+                film.toFilm
+                (
+                    patchi,
+                    film.primaryMesh().boundary()[primaryPatchi].deltaCoeffs()
+                )
             );
-            film.toRegion(patchi, deltaCoeffs);
 
-            scalarField alphap(alphaVoF.boundaryField()[primaryPatchi]);
-            film.toRegion(patchi, alphap);
-
-            scalarField rhop(rhoVoF.boundaryField()[primaryPatchi]);
-            film.toRegion(patchi, rhop);
-
-            vectorField Up(UVoF.boundaryField()[primaryPatchi]);
-            film.toRegion(patchi, Up);
-
-            scalarField hp(heVoF.boundaryField()[primaryPatchi]);
-            film.toRegion(patchi, hp);
-
-            scalarField Tp(TVoF.boundaryField()[primaryPatchi]);
-            film.toRegion(patchi, Tp);
-
-            scalarField Cpp(CpVoF.boundaryField()[primaryPatchi]);
-            film.toRegion(patchi, Cpp);
-
-            scalarField Vp
+            const scalarField alphaVoFp
             (
-                film.primaryMesh().boundary()[primaryPatchi]
-               .patchInternalField(film.primaryMesh().V())
+                film.toFilm(patchi, alphaVoF.boundaryField()[primaryPatchi])
+            );
+
+            const scalarField rhoVoFp
+            (
+                film.toFilm(patchi, rhoVoF.boundaryField()[primaryPatchi])
+            );
+
+            const vectorField UVoFp
+            (
+                film.toFilm(patchi, UVoF.boundaryField()[primaryPatchi])
+            );
+
+            const scalarField heVoFp
+            (
+                film.toFilm(patchi, heVoF.boundaryField()[primaryPatchi])
+            );
+
+            const scalarField VVoFp
+            (
+                film.toFilm
+                (
+                    patchi,
+                    film.primaryMesh().boundary()[primaryPatchi]
+                   .patchInternalField(film.primaryMesh().V())
+                )
             );
-            film.toRegion(patchi, Vp);
 
             const polyPatch& pp = pbm[patchi];
             const labelList& faceCells = pp.faceCells();
@@ -235,10 +241,11 @@ void VoFPatchTransfer::correct
 
                 scalar dMass = 0;
 
+                // Film->VoF transfer
                 if
                 (
-                    delta[celli] > 2*deltaFactorToVoF_/deltaCoeffs[facei]
-                 || alphap[facei] > alphaToVoF_
+                    delta[celli] > 2*deltaFactorToVoF_/deltaCoeffsVoF[facei]
+                 || alphaVoFp[facei] > alphaToVoF_
                 )
                 {
                     dMass =
@@ -249,19 +256,21 @@ void VoFPatchTransfer::correct
                     energyToTransfer[celli] += dMass*he[celli];
                 }
 
+                // VoF->film transfer
                 if
                 (
-                    alphap[facei] > 0
-                 && delta[celli] < 2*deltaFactorToFilm_/deltaCoeffs[facei]
-                 && alphap[facei] < alphaToFilm_
+                    alphaVoFp[facei] > 0
+                 && delta[celli] < 2*deltaFactorToFilm_/deltaCoeffsVoF[facei]
+                 && alphaVoFp[facei] < alphaToFilm_
                 )
                 {
                     dMass =
-                        -transferRateCoeff_*alphap[facei]*rhop[facei]*Vp[facei];
+                        -transferRateCoeff_
+                        *alphaVoFp[facei]*rhoVoFp[facei]*VVoFp[facei];
 
                     massToTransfer[celli] += dMass;
-                    momentumToTransfer[celli] += dMass*Up[facei];
-                    energyToTransfer[celli] += dMass*hp[facei];
+                    momentumToTransfer[celli] += dMass*UVoFp[facei];
+                    energyToTransfer[celli] += dMass*heVoFp[facei];
                 }
 
                 availableMass[celli] -= dMass;
diff --git a/src/lagrangian/parcel/submodels/Thermodynamic/SurfaceFilmModel/ThermoSurfaceFilm/ThermoSurfaceFilm.C b/src/lagrangian/parcel/submodels/Thermodynamic/SurfaceFilmModel/ThermoSurfaceFilm/ThermoSurfaceFilm.C
index 6275367ce7..401976ed86 100644
--- a/src/lagrangian/parcel/submodels/Thermodynamic/SurfaceFilmModel/ThermoSurfaceFilm/ThermoSurfaceFilm.C
+++ b/src/lagrangian/parcel/submodels/Thermodynamic/SurfaceFilmModel/ThermoSurfaceFilm/ThermoSurfaceFilm.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -620,7 +620,7 @@ bool Foam::ThermoSurfaceFilm<CloudType>::transferParcel
     {
         surfaceFilm& filmModel = this->surfaceFilmPtrs()[filmi];
 
-        if (filmModel.isRegionPatch(patchi))
+        if (filmModel.isFilmPatch(patchi))
         {
             const label facei = pp.whichFace(p.face());
 
diff --git a/src/surfaceFilmModels/derivedFvPatchFields/inclinedFilmNusseltHeight/inclinedFilmNusseltHeightFvPatchScalarField.C b/src/surfaceFilmModels/derivedFvPatchFields/inclinedFilmNusseltHeight/inclinedFilmNusseltHeightFvPatchScalarField.C
index 5de10b0e05..e073804ea4 100644
--- a/src/surfaceFilmModels/derivedFvPatchFields/inclinedFilmNusseltHeight/inclinedFilmNusseltHeightFvPatchScalarField.C
+++ b/src/surfaceFilmModels/derivedFvPatchFields/inclinedFilmNusseltHeight/inclinedFilmNusseltHeightFvPatchScalarField.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2012-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2012-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -111,7 +111,7 @@ void Foam::inclinedFilmNusseltHeightFvPatchScalarField::updateCoeffs()
 
     const label patchi = patch().index();
 
-    // retrieve the film region from the database
+    // retrieve the film film from the database
 
     const momentumSurfaceFilm& film =
         db().time().lookupObject<momentumSurfaceFilm>
diff --git a/src/surfaceFilmModels/derivedFvPatchFields/inclinedFilmNusseltInletVelocity/inclinedFilmNusseltInletVelocityFvPatchVectorField.C b/src/surfaceFilmModels/derivedFvPatchFields/inclinedFilmNusseltInletVelocity/inclinedFilmNusseltInletVelocityFvPatchVectorField.C
index 1d8b154b70..1a10375592 100644
--- a/src/surfaceFilmModels/derivedFvPatchFields/inclinedFilmNusseltInletVelocity/inclinedFilmNusseltInletVelocityFvPatchVectorField.C
+++ b/src/surfaceFilmModels/derivedFvPatchFields/inclinedFilmNusseltInletVelocity/inclinedFilmNusseltInletVelocityFvPatchVectorField.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2012-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2012-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -111,7 +111,7 @@ void Foam::inclinedFilmNusseltInletVelocityFvPatchVectorField::updateCoeffs()
 
     const label patchi = patch().index();
 
-    // Retrieve the film region from the database
+    // Retrieve the film film from the database
 
     const momentumSurfaceFilm& film =
         db().time().lookupObject<momentumSurfaceFilm>
diff --git a/src/surfaceFilmModels/derivedFvPatchFields/wallFunctions/alphatFilmWallFunction/alphatFilmWallFunctionFvPatchScalarField.C b/src/surfaceFilmModels/derivedFvPatchFields/wallFunctions/alphatFilmWallFunction/alphatFilmWallFunctionFvPatchScalarField.C
index ee6ef33ebb..54d13e5245 100644
--- a/src/surfaceFilmModels/derivedFvPatchFields/wallFunctions/alphatFilmWallFunction/alphatFilmWallFunctionFvPatchScalarField.C
+++ b/src/surfaceFilmModels/derivedFvPatchFields/wallFunctions/alphatFilmWallFunction/alphatFilmWallFunctionFvPatchScalarField.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -152,7 +152,7 @@ void alphatFilmWallFunctionFvPatchScalarField::updateCoeffs()
     const modelType& filmModel =
         db().time().lookupObject<modelType>(filmName_ + "Properties");
 
-    const label filmPatchi = filmModel.regionPatchID(patchi);
+    const label filmPatchi = filmModel.filmPatchID(patchi);
 
     tmp<volScalarField> mDotFilm(filmModel.primaryMassTrans());
     scalarField mDotFilmp = mDotFilm().boundaryField()[filmPatchi];
diff --git a/src/surfaceFilmModels/derivedFvPatchFields/wallFunctions/nutkFilmWallFunction/nutkFilmWallFunctionFvPatchScalarField.C b/src/surfaceFilmModels/derivedFvPatchFields/wallFunctions/nutkFilmWallFunction/nutkFilmWallFunctionFvPatchScalarField.C
index b2ad4f7569..9be8ad9003 100644
--- a/src/surfaceFilmModels/derivedFvPatchFields/wallFunctions/nutkFilmWallFunction/nutkFilmWallFunctionFvPatchScalarField.C
+++ b/src/surfaceFilmModels/derivedFvPatchFields/wallFunctions/nutkFilmWallFunction/nutkFilmWallFunctionFvPatchScalarField.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -68,7 +68,7 @@ tmp<scalarField> nutkFilmWallFunctionFvPatchScalarField::calcUTau
     const modelType& filmModel =
         db().time().lookupObject<modelType>(filmName_+ "Properties");
 
-    const label filmPatchi = filmModel.regionPatchID(patchi);
+    const label filmPatchi = filmModel.filmPatchID(patchi);
 
     tmp<volScalarField> mDotFilm(filmModel.primaryMassTrans());
     scalarField mDotFilmp = mDotFilm().boundaryField()[filmPatchi];
diff --git a/src/surfaceFilmModels/fvModels/surfaceFilms/surfaceFilms.H b/src/surfaceFilmModels/fvModels/surfaceFilms/surfaceFilms.H
index 8d8eb248a9..a51e4daa66 100644
--- a/src/surfaceFilmModels/fvModels/surfaceFilms/surfaceFilms.H
+++ b/src/surfaceFilmModels/fvModels/surfaceFilms/surfaceFilms.H
@@ -69,7 +69,7 @@ class surfaceFilms
         PtrList<thermoSurfaceFilm> surfaceFilms_;
 
         //- For each surface film model, the corresponding density name in the
-        //  primary region
+        //  primary film
         wordList surfaceFilmPrimaryRhoNames_;
 
         //- List of fields for which the fvModel adds source term
diff --git a/src/surfaceFilmModels/momentumSurfaceFilm/momentumSurfaceFilm.C b/src/surfaceFilmModels/momentumSurfaceFilm/momentumSurfaceFilm.C
index 77417946c5..af45981fdf 100644
--- a/src/surfaceFilmModels/momentumSurfaceFilm/momentumSurfaceFilm.C
+++ b/src/surfaceFilmModels/momentumSurfaceFilm/momentumSurfaceFilm.C
@@ -59,7 +59,7 @@ bool Foam::momentumSurfaceFilm::read()
 }
 
 
-void Foam::momentumSurfaceFilm::resetPrimaryRegionSourceTerms()
+void Foam::momentumSurfaceFilm::resetPrimaryFilmSourceTerms()
 {
     DebugInFunction << endl;
 
@@ -70,11 +70,11 @@ void Foam::momentumSurfaceFilm::resetPrimaryRegionSourceTerms()
 
 
 void Foam::momentumSurfaceFilm::
-transferPrimaryRegionThermoFields()
+transferPrimaryFilmThermoFields()
 {
     DebugInFunction << endl;
 
-    // Update fields from primary region via direct mapped
+    // Update fields from primary film via direct mapped
     // (coupled) boundary conditions
     UPrimary_.correctBoundaryConditions();
     p_.correctBoundaryConditions();
@@ -84,7 +84,7 @@ transferPrimaryRegionThermoFields()
 
 
 void Foam::momentumSurfaceFilm::
-transferPrimaryRegionSourceFields()
+transferPrimaryFilmSourceFields()
 {
     DebugInFunction << endl;
 
@@ -112,12 +112,12 @@ transferPrimaryRegionSourceFields()
         pSpPrimaryBf[patchi] *= rpriMagSfdeltaT;
     }
 
-    // Retrieve the source fields from the primary region
-    toRegion(rhoSp_, rhoSpPrimaryBf);
+    // Retrieve the source fields from the primary film
+    toFilm(rhoSp_, rhoSpPrimaryBf);
     rhoSp_.field() /= VbyA();
-    toRegion(USp_, USpPrimaryBf);
+    toFilm(USp_, USpPrimaryBf);
     USp_.field() /= VbyA();
-    toRegion(pSp_, pSpPrimaryBf);
+    toFilm(pSp_, pSpPrimaryBf);
 
     // update addedMassTotal counter
     if (time().writeTime())
@@ -158,7 +158,7 @@ Foam::momentumSurfaceFilm::pe()
     return volScalarField::New
     (
         typedName("pe"),
-        p_                             // Pressure (mapped from primary region)
+        p_                             // Pressure (mapped from primary film)
       - tpSp                           // Accumulated particle impingement
     );
 }
@@ -464,11 +464,11 @@ Foam::momentumSurfaceFilm::momentumSurfaceFilm
     const word& modelType,
     const fvMesh& primaryMesh,
     const dimensionedVector& g,
-    const word& regionType,
+    const word& filmType,
     const bool readFields
 )
 :
-    surfaceFilm(modelType, primaryMesh, g, regionType),
+    surfaceFilm(modelType, primaryMesh, g, filmType),
     phaseName_(coeffs_.lookupOrDefault("phase", word::null)),
     pimple_(mesh_),
 
@@ -829,7 +829,7 @@ Foam::momentumSurfaceFilm::momentumSurfaceFilm
 
     if (readFields)
     {
-        transferPrimaryRegionThermoFields();
+        transferPrimaryFilmThermoFields();
 
         correctCoverage();
 
@@ -907,15 +907,15 @@ void Foam::momentumSurfaceFilm::addSources
 }
 
 
-void Foam::momentumSurfaceFilm::preEvolveRegion()
+void Foam::momentumSurfaceFilm::preEvolveFilm()
 {
     DebugInFunction << endl;
 
-    surfaceFilm::preEvolveRegion();
+    surfaceFilm::preEvolveFilm();
 
-    transferPrimaryRegionThermoFields();
+    transferPrimaryFilmThermoFields();
 
-    transferPrimaryRegionSourceFields();
+    transferPrimaryFilmSourceFields();
 
     // Reset transfer fields
     availableMass_ = mass();
@@ -926,7 +926,7 @@ void Foam::momentumSurfaceFilm::preEvolveRegion()
 }
 
 
-void Foam::momentumSurfaceFilm::evolveRegion()
+void Foam::momentumSurfaceFilm::evolveFilm()
 {
     DebugInFunction << endl;
 
@@ -961,7 +961,7 @@ void Foam::momentumSurfaceFilm::evolveRegion()
     }
 
     // Reset source terms for next time integration
-    resetPrimaryRegionSourceTerms();
+    resetPrimaryFilmSourceTerms();
 }
 
 
diff --git a/src/surfaceFilmModels/momentumSurfaceFilm/momentumSurfaceFilm.H b/src/surfaceFilmModels/momentumSurfaceFilm/momentumSurfaceFilm.H
index 3e01e91e7d..be70646e44 100644
--- a/src/surfaceFilmModels/momentumSurfaceFilm/momentumSurfaceFilm.H
+++ b/src/surfaceFilmModels/momentumSurfaceFilm/momentumSurfaceFilm.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -125,7 +125,7 @@ protected:
 
             // Transfer fields
 
-                //- Film mass available for transfer to the primary region
+                //- Film mass available for transfer to the primary film
                 volScalarField primaryMassTrans_;
 
                 //- Film mass available for transfer to cloud
@@ -140,8 +140,8 @@ protected:
 
         // Source term fields
 
-            // Film region - registered to the film region mesh
-            // Note: need boundary value mapped from primary region, and then
+            // Film film - registered to the film film mesh
+            // Note: need boundary value mapped from primary film, and then
             // pushed into the patch internal field
 
                 //- Mass [kg/m^2/s]
@@ -154,20 +154,20 @@ protected:
                 volScalarField::Internal pSp_;
 
 
-            // Primary region - registered to the primary region mesh
+            // Primary film - registered to the primary film mesh
             // Internal use only - not read-in
 
-                //- Primary region mass source [kg]
+                //- Primary film mass source [kg]
                 volScalarField rhoSpPrimary_;
 
-                //- Primary region tangential momentum source [kg m/s]
+                //- Primary film tangential momentum source [kg m/s]
                 volVectorField USpPrimary_;
 
-                //- Primary region normal momentum source (pressure) [kg m/s]
+                //- Primary film normal momentum source (pressure) [kg m/s]
                 volScalarField pSpPrimary_;
 
 
-        // Fields mapped from primary region - registered to the film region
+        // Fields mapped from primary film - registered to the film film
         // Note: need both boundary AND patch internal fields to be mapped
 
             //- Velocity [m/s]
@@ -217,13 +217,13 @@ protected:
         virtual bool read();
 
         //- Reset source term fields
-        virtual void resetPrimaryRegionSourceTerms();
+        virtual void resetPrimaryFilmSourceTerms();
 
-        //- Transfer thermo fields from the primary region to the film region
-        virtual void transferPrimaryRegionThermoFields();
+        //- Transfer thermo fields from the primary film to the film film
+        virtual void transferPrimaryFilmThermoFields();
 
-        //- Transfer source fields from the primary region to the film region
-        virtual void transferPrimaryRegionSourceFields();
+        //- Transfer source fields from the primary film to the film film
+        virtual void transferPrimaryFilmSourceFields();
 
         //- Hydrostatic pressure coefficient
         tmp<surfaceScalarField> rhog() const;
@@ -249,7 +249,7 @@ protected:
         //- Continuity check
         virtual void continuityCheck();
 
-        //- Constrain a film region master/slave boundaries of a field to a
+        //- Constrain a film film master/slave boundaries of a field to a
         //  given value
         template<class Type>
         tmp<Type> constrainFilmField
@@ -294,7 +294,7 @@ public:
             const word& modelType,
             const fvMesh& primaryMesh,
             const dimensionedVector& g,
-            const word& regionType,
+            const word& filmType,
             const bool readFields = true
         );
 
@@ -369,7 +369,7 @@ public:
             tmp<volVectorField::Internal> Uw() const;
 
 
-        // Transfer fields - to the primary region
+        // Transfer fields - to the primary film
 
             //- Return mass transfer source - Eulerian phase only
             virtual tmp<volScalarField> primaryMassTrans() const;
@@ -389,7 +389,7 @@ public:
             //- External hook to add sources to the film
             virtual void addSources
             (
-                const label patchi,            // patchi on primary region
+                const label patchi,            // patchi on primary film
                 const label facei,             // facei of patchi
                 const scalar massSource,       // [kg]
                 const vector& momentumSource,  // [kg m/s] (tang'l momentum)
@@ -400,7 +400,7 @@ public:
 
          // Source fields (read/write access)
 
-            // Primary region
+            // Primary film
 
                 //- Momentum [kg/m/s^2]
                 inline volVectorField& USpPrimary();
@@ -412,7 +412,7 @@ public:
                 inline volScalarField& rhoSpPrimary();
 
 
-            // Film region
+            // Film film
 
                 //- Momentum [kg/m/s^2]
                 inline volVectorField::Internal& USp();
@@ -433,7 +433,7 @@ public:
                 inline const volScalarField::Internal& rhoSp() const;
 
 
-        // Fields mapped from primary region
+        // Fields mapped from primary film
 
             //- Velocity [m/s]
             inline const volVectorField& UPrimary() const;
@@ -476,13 +476,13 @@ public:
         // Evolution
 
             //- Pre-evolve film hook
-            virtual void preEvolveRegion();
+            virtual void preEvolveFilm();
 
             //- Evolve the film equations
-            virtual void evolveRegion();
+            virtual void evolveFilm();
 
 
-        // Primary region source fields
+        // Primary film source fields
 
             //- Return total mass source - Eulerian phase only
             virtual tmp<volScalarField::Internal> Srho() const;
diff --git a/src/surfaceFilmModels/submodels/momentum/ejectionModel/ejectionModelList/ejectionModelList.C b/src/surfaceFilmModels/submodels/momentum/ejectionModel/ejectionModelList/ejectionModelList.C
index d4c4779297..dca8dfa223 100644
--- a/src/surfaceFilmModels/submodels/momentum/ejectionModel/ejectionModelList/ejectionModelList.C
+++ b/src/surfaceFilmModels/submodels/momentum/ejectionModel/ejectionModelList/ejectionModelList.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -122,7 +122,7 @@ void ejectionModelList::correct
         im.correct(availableMass, massToEject, diameterToEject);
     }
 
-    // Push values to boundaries ready for transfer to the primary region
+    // Push values to boundaries ready for transfer to the primary film
     massToEject.correctBoundaryConditions();
     diameterToEject.correctBoundaryConditions();
 
diff --git a/src/surfaceFilmModels/submodels/momentum/transferModels/transferModelList/transferModelList.C b/src/surfaceFilmModels/submodels/momentum/transferModels/transferModelList/transferModelList.C
index 2cf50eead5..b7dc52d380 100644
--- a/src/surfaceFilmModels/submodels/momentum/transferModels/transferModelList/transferModelList.C
+++ b/src/surfaceFilmModels/submodels/momentum/transferModels/transferModelList/transferModelList.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2017-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2017-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -121,7 +121,7 @@ void transferModelList::correct
         );
     }
 
-    // Push values to boundaries ready for transfer to the primary region
+    // Push values to boundaries ready for transfer to the primary film
     massToTransfer.correctBoundaryConditions();
 
     const labelList& patchIDs = film().intCoupledPatchIDs();
@@ -155,7 +155,7 @@ void transferModelList::correct
         );
     }
 
-    // Push values to boundaries ready for transfer to the primary region
+    // Push values to boundaries ready for transfer to the primary film
     massToTransfer.correctBoundaryConditions();
     momentumToTransfer.correctBoundaryConditions();
     energyToTransfer.correctBoundaryConditions();
diff --git a/src/surfaceFilmModels/submodels/thermo/filmRadiationModel/primaryRadiation/primaryRadiation.C b/src/surfaceFilmModels/submodels/thermo/filmRadiationModel/primaryRadiation/primaryRadiation.C
index 5b7a7d2531..2f762ed6ff 100644
--- a/src/surfaceFilmModels/submodels/thermo/filmRadiationModel/primaryRadiation/primaryRadiation.C
+++ b/src/surfaceFilmModels/submodels/thermo/filmRadiationModel/primaryRadiation/primaryRadiation.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2012-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2012-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -86,8 +86,8 @@ void primaryRadiation::correct()
         film().primaryMesh().lookupObject<volScalarField>("qin")
     );
 
-    // Map the primary-side radiative flux to the region internal field
-    film().toRegion(qinFilm_, qinPrimary.boundaryField());
+    // Map the primary-side radiative flux to the film internal field
+    film().toFilm(qinFilm_, qinPrimary.boundaryField());
 }
 
 
diff --git a/src/surfaceFilmModels/submodels/thermo/filmRadiationModel/primaryRadiation/primaryRadiation.H b/src/surfaceFilmModels/submodels/thermo/filmRadiationModel/primaryRadiation/primaryRadiation.H
index b748489ca8..bc2331215a 100644
--- a/src/surfaceFilmModels/submodels/thermo/filmRadiationModel/primaryRadiation/primaryRadiation.H
+++ b/src/surfaceFilmModels/submodels/thermo/filmRadiationModel/primaryRadiation/primaryRadiation.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2012-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2012-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -26,7 +26,7 @@ Class
 
 Description
     Radiation model whereby the radiative heat flux is mapped from the primary
-    region
+    film
 
 SourceFiles
     primaryRadiation.C
@@ -56,7 +56,7 @@ class primaryRadiation
 {
     // Private Data
 
-        //- Incident radiative flux mapped from the primary region [kg/s^3]
+        //- Incident radiative flux mapped from the primary film [kg/s^3]
         volScalarField::Internal qinFilm_;
 
 
diff --git a/src/surfaceFilmModels/submodels/thermo/filmRadiationModel/standardRadiation/standardRadiation.C b/src/surfaceFilmModels/submodels/thermo/filmRadiationModel/standardRadiation/standardRadiation.C
index 7fa314a9ba..e72ea7e8af 100644
--- a/src/surfaceFilmModels/submodels/thermo/filmRadiationModel/standardRadiation/standardRadiation.C
+++ b/src/surfaceFilmModels/submodels/thermo/filmRadiationModel/standardRadiation/standardRadiation.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -88,8 +88,8 @@ void standardRadiation::correct()
         film().primaryMesh().lookupObject<volScalarField>("qin")
     );
 
-    // Map the primary-side radiative flux to the region internal field
-    film().toRegion(qinFilm_, qinPrimary.boundaryField());
+    // Map the primary-side radiative flux to the film internal field
+    film().toFilm(qinFilm_, qinPrimary.boundaryField());
 }
 
 
diff --git a/src/surfaceFilmModels/submodels/thermo/filmRadiationModel/standardRadiation/standardRadiation.H b/src/surfaceFilmModels/submodels/thermo/filmRadiationModel/standardRadiation/standardRadiation.H
index 778d296e7b..2a80823c5c 100644
--- a/src/surfaceFilmModels/submodels/thermo/filmRadiationModel/standardRadiation/standardRadiation.H
+++ b/src/surfaceFilmModels/submodels/thermo/filmRadiationModel/standardRadiation/standardRadiation.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -55,7 +55,7 @@ class standardRadiation
 {
     // Private Data
 
-        //- Radiative incident flux mapped from the primary region [kg/s^3]
+        //- Radiative incident flux mapped from the primary film [kg/s^3]
         volScalarField::Internal qinFilm_;
 
 
diff --git a/src/surfaceFilmModels/submodels/thermo/heatTransferModel/mappedConvectiveHeatTransfer/mappedConvectiveHeatTransfer.C b/src/surfaceFilmModels/submodels/thermo/heatTransferModel/mappedConvectiveHeatTransfer/mappedConvectiveHeatTransfer.C
index 6d5a768001..6dffc957b7 100644
--- a/src/surfaceFilmModels/submodels/thermo/heatTransferModel/mappedConvectiveHeatTransfer/mappedConvectiveHeatTransfer.C
+++ b/src/surfaceFilmModels/submodels/thermo/heatTransferModel/mappedConvectiveHeatTransfer/mappedConvectiveHeatTransfer.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -99,8 +99,8 @@ void mappedConvectiveHeatTransfer::correct()
     htcConvPrimary_.correctBoundaryConditions();
 
     // Map the primary-side convective heat transfer coefficient
-    // to the region internal field
-    film().toRegion(htcConvFilm_, htcConvPrimary_.boundaryField());
+    // to the film internal field
+    film().toFilm(htcConvFilm_, htcConvPrimary_.boundaryField());
 }
 
 
diff --git a/src/surfaceFilmModels/submodels/thermo/heatTransferModel/mappedConvectiveHeatTransfer/mappedConvectiveHeatTransfer.H b/src/surfaceFilmModels/submodels/thermo/heatTransferModel/mappedConvectiveHeatTransfer/mappedConvectiveHeatTransfer.H
index 85f4d5577c..ab1e58d1e0 100644
--- a/src/surfaceFilmModels/submodels/thermo/heatTransferModel/mappedConvectiveHeatTransfer/mappedConvectiveHeatTransfer.H
+++ b/src/surfaceFilmModels/submodels/thermo/heatTransferModel/mappedConvectiveHeatTransfer/mappedConvectiveHeatTransfer.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -56,10 +56,10 @@ class mappedConvectiveHeatTransfer
 {
     // Private Data
 
-        //- Heat transfer coefficient - primary region [W/m^2/K]
+        //- Heat transfer coefficient - primary film [W/m^2/K]
         volScalarField htcConvPrimary_;
 
-        //- Heat transfer coefficient - film region [W/m^2/K]
+        //- Heat transfer coefficient - film film [W/m^2/K]
         volScalarField::Internal htcConvFilm_;
 
 
diff --git a/src/surfaceFilmModels/submodels/thermo/phaseChangeModel/standardPhaseChange/standardPhaseChange.C b/src/surfaceFilmModels/submodels/thermo/phaseChangeModel/standardPhaseChange/standardPhaseChange.C
index eedbd8d6bb..2908ec8f88 100644
--- a/src/surfaceFilmModels/submodels/thermo/phaseChangeModel/standardPhaseChange/standardPhaseChange.C
+++ b/src/surfaceFilmModels/submodels/thermo/phaseChangeModel/standardPhaseChange/standardPhaseChange.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -165,10 +165,10 @@ void standardPhaseChange::correctModel
             }
             else
             {
-                // Primary region density [kg/m^3]
+                // Primary film density [kg/m^3]
                 const scalar rhoInfc = rhoInf[celli];
 
-                // Primary region viscosity [Pa.s]
+                // Primary film viscosity [Pa.s]
                 const scalar muInfc = muInf[celli];
 
                 // Reynolds number
@@ -197,7 +197,7 @@ void standardPhaseChange::correctModel
 
             dMass[celli] += dm;
 
-            // Assume that the vapour transferred to the primary region is
+            // Assume that the vapour transferred to the primary film is
             // already at temperature Tloc so that all heat required for
             // the phase-change is provided by the film
             dEnergy[celli] += dm*primarySpecieThermo.Hs(vapId(), pc, Tloc);
diff --git a/src/surfaceFilmModels/submodels/thermo/phaseChangeModel/waxSolventEvaporation/waxSolventEvaporation.C b/src/surfaceFilmModels/submodels/thermo/phaseChangeModel/waxSolventEvaporation/waxSolventEvaporation.C
index e26ab9285a..be41a4af68 100644
--- a/src/surfaceFilmModels/submodels/thermo/phaseChangeModel/waxSolventEvaporation/waxSolventEvaporation.C
+++ b/src/surfaceFilmModels/submodels/thermo/phaseChangeModel/waxSolventEvaporation/waxSolventEvaporation.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2017-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2017-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -238,7 +238,7 @@ void waxSolventEvaporation::correctModel
                 Ysolvent*Wsolvent/((1 - Ysolvent)*Wwax + Ysolvent*Wsolvent)
             );
 
-            // Primary region density [kg/m^3]
+            // Primary film density [kg/m^3]
             const scalar rhoInfc = rhoInf[celli];
 
             // Cell pressure [Pa]
@@ -276,7 +276,7 @@ void waxSolventEvaporation::correctModel
                 XsCoeff/(XsCoeff*Xsolvent*Wsolvent + (1 - Xs)*Wvap)
             );
 
-            // Primary region viscosity [Pa.s]
+            // Primary film viscosity [Pa.s]
             const scalar muInfc = muInf[celli];
 
             // Reynolds number
@@ -374,7 +374,7 @@ void waxSolventEvaporation::correctModel
 
         dMass += dm;
 
-        // Assume that the vapour transferred to the primary region is
+        // Assume that the vapour transferred to the primary film is
         // already at temperature Tloc so that all heat required for
         // the phase-change is provided by the film
         dEnergy += dm*primarySpecieThermo.Hs(vapId(), pInf, Tloc);
diff --git a/src/surfaceFilmModels/surfaceFilm/surfaceFilm.C b/src/surfaceFilmModels/surfaceFilm/surfaceFilm.C
index b18ae95f86..316bc8acef 100644
--- a/src/surfaceFilmModels/surfaceFilm/surfaceFilm.C
+++ b/src/surfaceFilmModels/surfaceFilm/surfaceFilm.C
@@ -59,56 +59,56 @@ bool Foam::surfaceFilm::read()
 
 Foam::label Foam::surfaceFilm::nbrCoupledPatchID
 (
-    const surfaceFilm& nbrRegion,
-    const label regionPatchi
+    const surfaceFilm& nbrFilm,
+    const label filmPatchi
 ) const
 {
     label nbrPatchi = -1;
 
-    // region
-    const fvMesh& nbrRegionMesh = nbrRegion.mesh();
+    // film
+    const fvMesh& nbrFilmMesh = nbrFilm.mesh();
 
     // boundary meshes
     const polyBoundaryMesh& pbm = mesh().boundaryMesh();
-    const polyBoundaryMesh& nbrPbm = nbrRegionMesh.boundaryMesh();
+    const polyBoundaryMesh& nbrPbm = nbrFilmMesh.boundaryMesh();
 
-    if (regionPatchi > pbm.size() - 1)
+    if (filmPatchi > pbm.size() - 1)
     {
         FatalErrorInFunction
-            << "region patch index out of bounds: "
-            << "region patch index = " << regionPatchi
+            << "film patch index out of bounds: "
+            << "film patch index = " << filmPatchi
             << ", maximum index = " << pbm.size() - 1
             << abort(FatalError);
     }
 
     const mappedPatchBase& mpb =
-        mappedPatchBase::getMap(pbm[regionPatchi]);
+        mappedPatchBase::getMap(pbm[filmPatchi]);
 
-    // sample patch name on the primary region
+    // sample patch name on the primary film
     const word& primaryPatchName = mpb.nbrPatchName();
 
-    // find patch on nbr region that has the same sample patch name
-    forAll(nbrRegion.intCoupledPatchIDs(), j)
+    // find patch on nbr film that has the same sample patch name
+    forAll(nbrFilm.intCoupledPatchIDs(), j)
     {
-        const label nbrRegionPatchi = nbrRegion.intCoupledPatchIDs()[j];
+        const label nbrFilmPatchi = nbrFilm.intCoupledPatchIDs()[j];
 
         const mappedPatchBase& mpb =
-            mappedPatchBase::getMap(nbrPbm[nbrRegionPatchi]);
+            mappedPatchBase::getMap(nbrPbm[nbrFilmPatchi]);
 
         if (mpb.nbrPatchName() == primaryPatchName)
         {
-            nbrPatchi = nbrRegionPatchi;
+            nbrPatchi = nbrFilmPatchi;
             break;
         }
     }
 
     if (nbrPatchi == -1)
     {
-        const polyPatch& p = mesh().boundaryMesh()[regionPatchi];
+        const polyPatch& p = mesh().boundaryMesh()[filmPatchi];
 
         FatalErrorInFunction
             << "Unable to find patch pair for local patch "
-            << p.name() << " and region " << nbrRegion.name()
+            << p.name() << " and film " << nbrFilm.name()
             << abort(FatalError);
     }
 
@@ -123,14 +123,14 @@ Foam::surfaceFilm::surfaceFilm
     const word& modelType,
     const fvMesh& primaryMesh,
     const dimensionedVector& g,
-    const word& regionType
+    const word& filmType
 )
 :
     IOdictionary
     (
         IOobject
         (
-            regionType + "Properties",
+            filmType + "Properties",
             primaryMesh.time().constant(),
             primaryMesh.time(),
             IOobject::MUST_READ,
@@ -141,12 +141,12 @@ Foam::surfaceFilm::surfaceFilm
     time_(primaryMesh.time()),
     infoOutput_(true),
     modelType_(modelType),
-    regionName_(lookup("regionName")),
+    filmName_(lookup("filmName")),
     mesh_
     (
         IOobject
         (
-            regionName_,
+            filmName_,
             time_.name(),
             time_,
             IOobject::MUST_READ
@@ -201,16 +201,16 @@ Foam::surfaceFilm::surfaceFilm
 
     forAll(rbm, patchi)
     {
-        const polyPatch& regionPatch = rbm[patchi];
+        const polyPatch& filmPatch = rbm[patchi];
 
-        if (isA<mappedPatchBase>(regionPatch))
+        if (isA<mappedPatchBase>(filmPatch))
         {
             intCoupledPatchIDs.append(patchi);
 
-            nBoundaryFaces += regionPatch.faceCells().size();
+            nBoundaryFaces += filmPatch.faceCells().size();
 
             const mappedPatchBase& mapPatch =
-                refCast<const mappedPatchBase>(regionPatch);
+                refCast<const mappedPatchBase>(filmPatch);
 
             if
             (
@@ -232,8 +232,8 @@ Foam::surfaceFilm::surfaceFilm
     if (returnReduce(nBoundaryFaces, sumOp<label>()) == 0)
     {
         WarningInFunction
-            << "Region model has no mapped boundary conditions - transfer "
-            << "between regions will not be possible" << endl;
+            << "Film model has no mapped boundary conditions - transfer "
+            << "between films will not be possible" << endl;
     }
 
     if (!outputPropertiesPtr_.valid())
@@ -244,9 +244,9 @@ Foam::surfaceFilm::surfaceFilm
             (
                 IOobject
                 (
-                    regionName_ + "OutputProperties",
+                    filmName_ + "OutputProperties",
                     time_.name(),
-                    "uniform"/regionName_,
+                    "uniform"/filmName_,
                     primaryMesh_,
                     IOobject::READ_IF_PRESENT,
                     IOobject::NO_WRITE
@@ -275,8 +275,8 @@ Foam::surfaceFilm::surfaceFilm
     if (nBoundaryFaces != mesh_.nCells())
     {
         FatalErrorInFunction
-            << "Number of primary region coupled boundary faces not equal to "
-            << "the number of cells in the local region" << nl << nl
+            << "Number of primary film coupled boundary faces not equal to "
+            << "the number of cells in the local film" << nl << nl
             << "Number of cells = " << mesh_.nCells() << nl
             << "Boundary faces  = " << nBoundaryFaces << nl
             << abort(FatalError);
@@ -348,14 +348,14 @@ Foam::surfaceFilm::passivePatchIDs() const
 
 void Foam::surfaceFilm::evolve()
 {
-    Info<< "\nEvolving " << modelType_ << " for region "
+    Info<< "\nEvolving " << modelType_ << " for film "
         << mesh_.name() << endl;
 
-    preEvolveRegion();
+    preEvolveFilm();
 
-    evolveRegion();
+    evolveFilm();
 
-    postEvolveRegion();
+    postEvolveFilm();
 
     // Provide some feedback
     if (infoOutput_)
@@ -378,15 +378,15 @@ void Foam::surfaceFilm::evolve()
 }
 
 
-void Foam::surfaceFilm::preEvolveRegion()
+void Foam::surfaceFilm::preEvolveFilm()
 {}
 
 
-void Foam::surfaceFilm::evolveRegion()
+void Foam::surfaceFilm::evolveFilm()
 {}
 
 
-void Foam::surfaceFilm::postEvolveRegion()
+void Foam::surfaceFilm::postEvolveFilm()
 {}
 
 
diff --git a/src/surfaceFilmModels/surfaceFilm/surfaceFilm.H b/src/surfaceFilmModels/surfaceFilm/surfaceFilm.H
index 05f3580102..1093827021 100644
--- a/src/surfaceFilmModels/surfaceFilm/surfaceFilm.H
+++ b/src/surfaceFilmModels/surfaceFilm/surfaceFilm.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -67,10 +67,10 @@ protected:
         //- Model type
         const word modelType_;
 
-        //- Region name
-        word regionName_;
+        //- Film name
+        word filmName_;
 
-        //- Region mesh
+        //- Film mesh
         fvMesh mesh_;
 
         //- Model coefficients dictionary
@@ -82,10 +82,10 @@ protected:
 
         // Addressing
 
-            //- List of patch IDs on the primary region coupled to this region
+            //- List of patch IDs on the primary film coupled to this film
             labelList primaryPatchIDs_;
 
-            //- List of patch IDs internally coupled with the primary region
+            //- List of patch IDs internally coupled with the primary film
             labelList intCoupledPatchIDs_;
 
             //- List of patch IDs opposite to internally coupled patches
@@ -127,7 +127,7 @@ public:
             const word& modelType,
             const fvMesh& mesh,
             const dimensionedVector& g,
-            const word& regionType
+            const word& filmType
         );
 
         //- Disallow default bitwise copy construction
@@ -148,7 +148,7 @@ public:
             //- Return the reference to the primary mesh
             inline const fvMesh& primaryMesh() const;
 
-            //- Return the region mesh
+            //- Return the film mesh
             inline const fvMesh& mesh() const;
 
             //- Return the information flag
@@ -170,7 +170,7 @@ public:
             inline const dimensionedVector& g() const;
 
 
-            // Region geometry
+            // Film geometry
 
                 //- Return the patch normal vectors
                 const volVectorField& nHat() const;
@@ -183,24 +183,24 @@ public:
 
             // Addressing
 
-                //- Return true if patchi on the local region is a coupled
-                //  patch to the primary region
-                inline bool isCoupledPatch(const label regionPatchi) const;
+                //- Return true if patchi on the film is a coupled
+                //  patch to the primary film
+                inline bool isCoupledPatch(const label filmPatchi) const;
 
-                //- Return true if patchi on the primary region is a coupled
-                //  patch to the local region
-                inline bool isRegionPatch(const label primaryPatchi) const;
+                //- Return true if patchi on the primary film is a coupled
+                //  patch to the film
+                inline bool isFilmPatch(const label primaryPatchi) const;
 
-                //- Return the list of patch IDs on the primary region coupled
-                //  to this region
+                //- Return the list of patch IDs on the primary film coupled
+                //  to this film
                 inline const labelList& primaryPatchIDs() const;
 
                 //- Return the list of patch IDs internally coupled with the
-                //  primary region
+                //  primary film
                 inline const labelList& intCoupledPatchIDs() const;
 
-                //- Return region ID corresponding to primaryPatchID
-                inline label regionPatchID(const label primaryPatchID) const;
+                //- Return film ID corresponding to primaryPatchID
+                inline label filmPatchID(const label primaryPatchID) const;
 
                 //- Return the list of patch IDs opposite to internally
                 //  coupled patches
@@ -211,39 +211,47 @@ public:
 
             //- Return boundary types for mapped field patches
             //  Also maps internal field value
-            //  Mapping region prescribed by underlying mapped poly patch
+            //  Mapping film prescribed by underlying mapped poly patch
             template<class Type>
             wordList mappedFieldAndInternalPatchTypes() const;
 
         // Helper
 
             //- Return the coupled patch ID paired with coupled patch
-            //  regionPatchi
+            //  filmPatchi
             label nbrCoupledPatchID
             (
-                const surfaceFilm& nbrRegion,
-                const label regionPatchi
+                const surfaceFilm& nbrFilm,
+                const label filmPatchi
             ) const;
 
-            //- Convert a local region field to the primary region
+            //- Convert a film field to the primary film
             template<class Type>
             void toPrimary
             (
-                const label regionPatchi,
-                Field<Type>& regionField
+                const label filmPatchi,
+                Field<Type>& filmField
             ) const;
 
-            //- Convert a primary region field to the local region
+            //- Convert a primary film field to the film
             template<class Type>
-            void toRegion
+            tmp<Field<Type>> toFilm
             (
-                const label regionPatchi,
-                Field<Type>& primaryFieldField
+                const label filmPatchi,
+                const Field<Type>& primaryPatchField
             ) const;
 
-            //- Return a primary patch field mapped the local region
+            //- Convert a primary film field to the film
             template<class Type>
-            void toRegion
+            tmp<Field<Type>> toFilm
+            (
+                const label filmPatchi,
+                const tmp<Field<Type>> & primaryPatchField
+            ) const;
+
+            //- Return a primary patch field mapped the film
+            template<class Type>
+            void toFilm
             (
                 Field<Type>& rf,
                 const typename VolField<Type>::Boundary& pBf
@@ -274,7 +282,7 @@ public:
             virtual tmp<volScalarField> sigma() const = 0;
 
 
-        // Transfer fields - to the primary region
+        // Transfer fields - to the primary film
 
             //- Return mass transfer source - Eulerian phase only
             virtual tmp<volScalarField> primaryMassTrans() const = 0;
@@ -299,17 +307,17 @@ public:
                 const scalar energySource
             ) = 0;
 
-            //- Main driver routing to evolve the region - calls other evolves
+            //- Main driver routing to evolve the film - calls other evolves
             virtual void evolve();
 
-            //- Pre-evolve region
-            virtual void preEvolveRegion();
+            //- Pre-evolve film
+            virtual void preEvolveFilm();
 
-            //- Evolve the region
-            virtual void evolveRegion();
+            //- Evolve the film
+            virtual void evolveFilm();
 
-            //- Post-evolve region
-            virtual void postEvolveRegion();
+            //- Post-evolve film
+            virtual void postEvolveFilm();
 
 
         // I-O
diff --git a/src/surfaceFilmModels/surfaceFilm/surfaceFilmI.H b/src/surfaceFilmModels/surfaceFilm/surfaceFilmI.H
index 4c6b8d6f3e..8949dbdcc2 100644
--- a/src/surfaceFilmModels/surfaceFilm/surfaceFilmI.H
+++ b/src/surfaceFilmModels/surfaceFilm/surfaceFilmI.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -89,12 +89,12 @@ inline Foam::IOdictionary& Foam::surfaceFilm::outputProperties()
 
 inline bool Foam::surfaceFilm::isCoupledPatch
 (
-    const label regionPatchi
+    const label filmPatchi
 ) const
 {
     forAll(intCoupledPatchIDs_, i)
     {
-        if (intCoupledPatchIDs_[i] == regionPatchi)
+        if (intCoupledPatchIDs_[i] == filmPatchi)
         {
             return true;
         }
@@ -104,7 +104,7 @@ inline bool Foam::surfaceFilm::isCoupledPatch
 }
 
 
-inline bool Foam::surfaceFilm::isRegionPatch
+inline bool Foam::surfaceFilm::isFilmPatch
 (
     const label primaryPatchi
 ) const
@@ -133,7 +133,7 @@ inline const Foam::labelList& Foam::surfaceFilm::intCoupledPatchIDs() const
 }
 
 
-inline Foam::label Foam::surfaceFilm::regionPatchID
+inline Foam::label Foam::surfaceFilm::filmPatchID
 (
     const label primaryPatchID
 ) const
diff --git a/src/surfaceFilmModels/surfaceFilm/surfaceFilmTemplates.C b/src/surfaceFilmModels/surfaceFilm/surfaceFilmTemplates.C
index d6977045b0..77946b52f8 100644
--- a/src/surfaceFilmModels/surfaceFilm/surfaceFilmTemplates.C
+++ b/src/surfaceFilmModels/surfaceFilm/surfaceFilmTemplates.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -32,59 +32,90 @@ License
 template<class Type>
 void Foam::surfaceFilm::toPrimary
 (
-    const label regionPatchi,
-    Field<Type>& regionField
+    const label filmPatchi,
+    Field<Type>& filmField
 ) const
 {
     forAll(intCoupledPatchIDs_, i)
     {
-        if (intCoupledPatchIDs_[i] == regionPatchi)
+        if (intCoupledPatchIDs_[i] == filmPatchi)
         {
             const mappedPatchBase& mpb =
                 refCast<const mappedPatchBase>
                 (
-                    mesh().boundaryMesh()[regionPatchi]
+                    mesh().boundaryMesh()[filmPatchi]
                 );
-            regionField = mpb.reverseDistribute(regionField);
+            filmField = mpb.reverseDistribute(filmField);
             return;
         }
     }
 
     FatalErrorInFunction
-        << "Region patch ID " << regionPatchi << " not found in region mesh"
+        << "Film patch ID " << filmPatchi << " not found in film mesh"
         << abort(FatalError);
 }
 
 
 template<class Type>
-void Foam::surfaceFilm::toRegion
+Foam::tmp<Foam::Field<Type>> Foam::surfaceFilm::toFilm
 (
-    const label regionPatchi,
-    Field<Type>& primaryField
+    const label filmPatchi,
+    const Field<Type>& primaryPatchField
 ) const
 {
     forAll(intCoupledPatchIDs_, i)
     {
-        if (intCoupledPatchIDs_[i] == regionPatchi)
+        if (intCoupledPatchIDs_[i] == filmPatchi)
         {
             const mappedPatchBase& mpb =
                 refCast<const mappedPatchBase>
                 (
-                    mesh().boundaryMesh()[regionPatchi]
+                    mesh().boundaryMesh()[filmPatchi]
                 );
-            primaryField = mpb.distribute(primaryField);
-            return;
+
+            return mpb.distribute(primaryPatchField);
         }
     }
 
     FatalErrorInFunction
-        << "Region patch ID " << regionPatchi << " not found in region mesh"
+        << "Film patch ID " << filmPatchi << " not found in film mesh"
         << abort(FatalError);
+
+    return tmp<Field<Type>>(nullptr);
 }
 
 
 template<class Type>
-void Foam::surfaceFilm::toRegion
+Foam::tmp<Foam::Field<Type>> Foam::surfaceFilm::toFilm
+(
+    const label filmPatchi,
+    const tmp<Field<Type>>& tprimaryPatchField
+) const
+{
+    forAll(intCoupledPatchIDs_, i)
+    {
+        if (intCoupledPatchIDs_[i] == filmPatchi)
+        {
+            const mappedPatchBase& mpb =
+                refCast<const mappedPatchBase>
+                (
+                    mesh().boundaryMesh()[filmPatchi]
+                );
+
+            return mpb.distribute(tprimaryPatchField);
+        }
+    }
+
+    FatalErrorInFunction
+        << "Film patch ID " << filmPatchi << " not found in film mesh"
+        << abort(FatalError);
+
+    return tmp<Field<Type>>(nullptr);
+}
+
+
+template<class Type>
+void Foam::surfaceFilm::toFilm
 (
     Field<Type>& rf,
     const typename VolField<Type>::Boundary& pBf
@@ -92,16 +123,16 @@ void Foam::surfaceFilm::toRegion
 {
     forAll(intCoupledPatchIDs_, i)
     {
-        const label regionPatchi = intCoupledPatchIDs_[i];
+        const label filmPatchi = intCoupledPatchIDs_[i];
         const label primaryPatchi = primaryPatchIDs_[i];
 
-        const polyPatch& regionPatch =
-            mesh().boundaryMesh()[regionPatchi];
+        const polyPatch& filmPatch =
+            mesh().boundaryMesh()[filmPatchi];
 
         const mappedPatchBase& mpb =
-            refCast<const mappedPatchBase>(regionPatch);
+            refCast<const mappedPatchBase>(filmPatch);
 
-        UIndirectList<Type>(rf, regionPatch.faceCells()) =
+        UIndirectList<Type>(rf, filmPatch.faceCells()) =
             mpb.distribute(pBf[primaryPatchi]);
     }
 }
diff --git a/src/surfaceFilmModels/thermoSurfaceFilm/thermoSurfaceFilm.C b/src/surfaceFilmModels/thermoSurfaceFilm/thermoSurfaceFilm.C
index eb6b83e523..a5875ae644 100644
--- a/src/surfaceFilmModels/thermoSurfaceFilm/thermoSurfaceFilm.C
+++ b/src/surfaceFilmModels/thermoSurfaceFilm/thermoSurfaceFilm.C
@@ -53,23 +53,23 @@ bool Foam::thermoSurfaceFilm::read()
 }
 
 
-void Foam::thermoSurfaceFilm::resetPrimaryRegionSourceTerms()
+void Foam::thermoSurfaceFilm::resetPrimaryFilmSourceTerms()
 {
     DebugInFunction << endl;
 
-    momentumSurfaceFilm::resetPrimaryRegionSourceTerms();
+    momentumSurfaceFilm::resetPrimaryFilmSourceTerms();
 
     hSpPrimary_ == dimensionedScalar(hSp_.dimensions(), 0);
 }
 
 
-void Foam::thermoSurfaceFilm::transferPrimaryRegionThermoFields()
+void Foam::thermoSurfaceFilm::transferPrimaryFilmThermoFields()
 {
     DebugInFunction << endl;
 
-    momentumSurfaceFilm::transferPrimaryRegionThermoFields();
+    momentumSurfaceFilm::transferPrimaryFilmThermoFields();
 
-    // Update primary region fields on local region via direct mapped (coupled)
+    // Update primary film fields on local film via direct mapped (coupled)
     // boundary conditions
     TPrimary_.correctBoundaryConditions();
     forAll(YPrimary_, i)
@@ -79,11 +79,11 @@ void Foam::thermoSurfaceFilm::transferPrimaryRegionThermoFields()
 }
 
 
-void Foam::thermoSurfaceFilm::transferPrimaryRegionSourceFields()
+void Foam::thermoSurfaceFilm::transferPrimaryFilmSourceFields()
 {
     DebugInFunction << endl;
 
-    momentumSurfaceFilm::transferPrimaryRegionSourceFields();
+    momentumSurfaceFilm::transferPrimaryFilmSourceFields();
 
     volScalarField::Boundary& hSpPrimaryBf = hSpPrimary_.boundaryFieldRef();
 
@@ -99,8 +99,8 @@ void Foam::thermoSurfaceFilm::transferPrimaryRegionSourceFields()
         hSpPrimaryBf[patchi] *= rpriMagSfdeltaT;
     }
 
-    // Retrieve the source fields from the primary region
-    toRegion(hSp_, hSpPrimaryBf);
+    // Retrieve the source fields from the primary film
+    toFilm(hSp_, hSpPrimaryBf);
     hSp_.field() /= VbyA();
 }
 
@@ -199,7 +199,7 @@ Foam::tmp<Foam::fvScalarMatrix> Foam::thermoSurfaceFilm::q
 
     return
     (
-        // Heat-transfer to the primary region
+        // Heat-transfer to the primary film
       - fvm::Sp((htcs_->h()/VbyA())/Cpv, h)
       + (htcs_->h()/VbyA())*(h()/Cpv + coverage*(TPrimary_() - T))
 
@@ -241,11 +241,11 @@ Foam::thermoSurfaceFilm::thermoSurfaceFilm
     const word& modelType,
     const fvMesh& primaryMesh,
     const dimensionedVector& g,
-    const word& regionType,
+    const word& filmType,
     const bool readFields
 )
 :
-    momentumSurfaceFilm(modelType, primaryMesh, g, regionType, false),
+    momentumSurfaceFilm(modelType, primaryMesh, g, filmType, false),
 
     primaryThermo_
     (
@@ -307,7 +307,7 @@ Foam::thermoSurfaceFilm::thermoSurfaceFilm
     (
         IOobject
         (
-            "T", // Same name as T on primary region to enable mapping
+            "T", // Same name as T on primary film to enable mapping
             time().name(),
             mesh(),
             IOobject::NO_READ,
@@ -391,7 +391,7 @@ Foam::thermoSurfaceFilm::thermoSurfaceFilm
 
     if (readFields)
     {
-        transferPrimaryRegionThermoFields();
+        transferPrimaryFilmThermoFields();
 
         correctCoverage();
 
@@ -448,16 +448,16 @@ void Foam::thermoSurfaceFilm::addSources
 }
 
 
-void Foam::thermoSurfaceFilm::preEvolveRegion()
+void Foam::thermoSurfaceFilm::preEvolveFilm()
 {
     DebugInFunction << endl;
 
-    momentumSurfaceFilm::preEvolveRegion();
+    momentumSurfaceFilm::preEvolveFilm();
     primaryEnergyTrans_ == dimensionedScalar(dimEnergy, 0);
 }
 
 
-void Foam::thermoSurfaceFilm::evolveRegion()
+void Foam::thermoSurfaceFilm::evolveFilm()
 {
     DebugInFunction << endl;
 
@@ -495,7 +495,7 @@ void Foam::thermoSurfaceFilm::evolveRegion()
     }
 
     // Reset source terms for next time integration
-    resetPrimaryRegionSourceTerms();
+    resetPrimaryFilmSourceTerms();
 }
 
 
diff --git a/src/surfaceFilmModels/thermoSurfaceFilm/thermoSurfaceFilm.H b/src/surfaceFilmModels/thermoSurfaceFilm/thermoSurfaceFilm.H
index 318ef81b44..23fa176b06 100644
--- a/src/surfaceFilmModels/thermoSurfaceFilm/thermoSurfaceFilm.H
+++ b/src/surfaceFilmModels/thermoSurfaceFilm/thermoSurfaceFilm.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -71,10 +71,10 @@ protected:
 
         // Thermo properties
 
-            //- Reference to the primary region thermo
+            //- Reference to the primary film thermo
             const fluidThermo& primaryThermo_;
 
-            // Transfer fields - to the primary region
+            // Transfer fields - to the primary film
 
                 //- Film energy transfer
                 volScalarField primaryEnergyTrans_;
@@ -100,22 +100,22 @@ protected:
 
         // Source term fields
 
-            // Film region - registered to the film region mesh
-            // Note: need boundary value mapped from primary region, and then
+            // Film film - registered to the film film mesh
+            // Note: need boundary value mapped from primary film, and then
             // pushed into the patch internal field
 
                 //- Energy [J/m2/s]
                 volScalarField::Internal hSp_;
 
 
-            // Primary region - registered to the primary region mesh
+            // Primary film - registered to the primary film mesh
             // Internal use only - not read-in
 
                 //- Energy [J/m2/s]
                 volScalarField hSpPrimary_;
 
 
-        // Fields mapped from primary region - registered to the film region
+        // Fields mapped from primary film - registered to the film film
         // Note: need both boundary AND patch internal fields to be mapped
 
             //- Temperature [K]
@@ -128,7 +128,7 @@ protected:
         // Sub-models
 
             //- Heat transfer coefficient between film surface and primary
-            //  region [W/m^2/K]
+            //  film [W/m^2/K]
             autoPtr<surfaceFilmModels::heatTransferModel> htcs_;
 
             //- Heat transfer coefficient between wall and film [W/m^2/K]
@@ -156,13 +156,13 @@ protected:
         virtual bool read();
 
         //- Reset source term fields
-        virtual void resetPrimaryRegionSourceTerms();
+        virtual void resetPrimaryFilmSourceTerms();
 
-        //- Transfer thermo fields from the primary region to the film region
-        virtual void transferPrimaryRegionThermoFields();
+        //- Transfer thermo fields from the primary film to the film film
+        virtual void transferPrimaryFilmThermoFields();
 
-        //- Transfer source fields from the primary region to the film region
-        virtual void transferPrimaryRegionSourceFields();
+        //- Transfer source fields from the primary film to the film film
+        virtual void transferPrimaryFilmSourceFields();
 
         //- Correct film coverage field
         virtual void correctCoverage();
@@ -194,7 +194,7 @@ public:
             const word& modelType,
             const fvMesh& primaryMesh,
             const dimensionedVector& g,
-            const word& regionType,
+            const word& filmType,
             const bool readFields = true
         );
 
@@ -210,7 +210,7 @@ public:
 
         // Thermo properties
 
-            //- Return const reference to the primary region thermo object
+            //- Return const reference to the primary film thermo object
             inline const fluidThermo& primaryThermo() const;
 
 
@@ -230,7 +230,7 @@ public:
             //- External hook to add sources to the film
             virtual void addSources
             (
-                const label patchi,            // patchi on primary region
+                const label patchi,            // patchi on primary film
                 const label facei,             // facei of patchi
                 const scalar massSource,       // [kg]
                 const vector& momentumSource,  // [kg m/s] (tangential momentum)
@@ -241,19 +241,19 @@ public:
 
         // Source term fields
 
-            // Film region
+            // Film film
 
                 //- Energy [J/m2/s]
                 inline const volScalarField::Internal& hSp() const;
 
 
-            // Primary region
+            // Primary film
 
                 //- Energy [J/m2/s]
                 inline const volScalarField& hSpPrimary() const;
 
 
-        // Fields mapped from the primary region
+        // Fields mapped from the primary film
 
             //- Temperature [K]
             inline const volScalarField& TPrimary() const;
@@ -283,15 +283,15 @@ public:
         // Evolution
 
             //- Pre-evolve film hook
-            virtual void preEvolveRegion();
+            virtual void preEvolveFilm();
 
             //- Evolve the film equations
-            virtual void evolveRegion();
+            virtual void evolveFilm();
 
 
         // Source fields
 
-            // Mapped into primary region
+            // Mapped into primary film
 
                 //- Return mass source for specie i - Eulerian phase only
                 virtual tmp<volScalarField::Internal> SYi