diff --git a/applications/solvers/modules/isothermalFilm/Make/files b/applications/solvers/modules/isothermalFilm/Make/files
index a0ae4a33dd..1e08d75d2f 100644
--- a/applications/solvers/modules/isothermalFilm/Make/files
+++ b/applications/solvers/modules/isothermalFilm/Make/files
@@ -19,6 +19,7 @@ patches/mappedFilmSurface/mappedFilmSurfaceFvPatch/mappedFilmSurfaceFvPatch.C
 derivedFvPatchFields/alphaOne/alphaOneFvPatchScalarField.C
 derivedFvPatchFields/filmContactAngle/filmContactAngleFvPatchScalarField.C
 derivedFvPatchFields/mappedFilmPressure/mappedFilmPressureFvPatchScalarField.C
+derivedFvPatchFields/filmSurfaceVelocity/filmSurfaceVelocityFvPatchVectorField.C
 
 filmGaussGrad/filmGaussGrads.C
 
diff --git a/applications/solvers/modules/isothermalFilm/derivedFvPatchFields/filmSurfaceVelocity/filmSurfaceVelocityFvPatchVectorField.C b/applications/solvers/modules/isothermalFilm/derivedFvPatchFields/filmSurfaceVelocity/filmSurfaceVelocityFvPatchVectorField.C
new file mode 100644
index 0000000000..20512e2dd2
--- /dev/null
+++ b/applications/solvers/modules/isothermalFilm/derivedFvPatchFields/filmSurfaceVelocity/filmSurfaceVelocityFvPatchVectorField.C
@@ -0,0 +1,182 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Copyright (C) 2023 OpenFOAM Foundation
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+\*---------------------------------------------------------------------------*/
+
+#include "filmSurfaceVelocityFvPatchVectorField.H"
+#include "momentumTransportModel.H"
+#include "mappedPatchBase.H"
+#include "addToRunTimeSelectionTable.H"
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::filmSurfaceVelocityFvPatchVectorField::
+filmSurfaceVelocityFvPatchVectorField
+(
+    const fvPatch& p,
+    const DimensionedField<vector, volMesh>& iF
+)
+:
+    mixedFvPatchField<vector>(p, iF),
+    Cs_(0)
+{
+    refValue() = Zero;
+    refGrad() = Zero;
+    valueFraction() = 0;
+}
+
+
+Foam::filmSurfaceVelocityFvPatchVectorField::
+filmSurfaceVelocityFvPatchVectorField
+(
+    const fvPatch& p,
+    const DimensionedField<vector, volMesh>& iF,
+    const dictionary& dict
+)
+:
+    mixedFvPatchField<vector>(p, iF, dict, false),
+    Cs_(dict.lookup<scalar>("Cs"))
+{
+    refValue() = Zero;
+    refGrad() = Zero;
+    valueFraction() = 0;
+
+    if (dict.found("value"))
+    {
+        fvPatchVectorField::operator=
+        (
+            vectorField("value", dict, p.size())
+        );
+    }
+    else
+    {
+        // If the value entry is not present initialise to zero-gradient
+        fvPatchVectorField::operator=(patchInternalField());
+    }
+}
+
+
+Foam::filmSurfaceVelocityFvPatchVectorField::
+filmSurfaceVelocityFvPatchVectorField
+(
+    const filmSurfaceVelocityFvPatchVectorField& ptf,
+    const fvPatch& p,
+    const DimensionedField<vector, volMesh>& iF,
+    const fvPatchFieldMapper& mapper
+)
+:
+    mixedFvPatchField<vector>(ptf, p, iF, mapper),
+    Cs_(ptf.Cs_)
+{}
+
+
+Foam::filmSurfaceVelocityFvPatchVectorField::
+filmSurfaceVelocityFvPatchVectorField
+(
+    const filmSurfaceVelocityFvPatchVectorField& ptf,
+    const DimensionedField<vector, volMesh>& iF
+)
+:
+    mixedFvPatchField<vector>(ptf, iF),
+    Cs_(ptf.Cs_)
+{}
+
+
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
+void Foam::filmSurfaceVelocityFvPatchVectorField::updateCoeffs()
+{
+    if (updated())
+    {
+        return;
+    }
+
+    // Since we're inside initEvaluate/evaluate there might be processor
+    // comms underway. Change the tag we use.
+    const int oldTag = UPstream::msgType();
+    UPstream::msgType() = oldTag + 1;
+
+    // Get the coupling information from the mappedPatchBase
+    const mappedPatchBase& mpp = mappedPatchBase::getMap(patch().patch());
+    const label patchiNbr = mpp.nbrPolyPatch().index();
+    const fvPatch& patchNbr =
+        refCast<const fvMesh>(mpp.nbrMesh()).boundary()[patchiNbr];
+
+    const vectorField UpNbr =
+        patchNbr.lookupPatchField<volVectorField, scalar>("U")
+       .patchInternalField();
+
+    // Set the reference value to the neighbouring fluid internal velocity
+    refValue() = mpp.distribute(UpNbr);
+
+    // Remove the normal component of the surface vel
+    const vectorField n(patch().nf());
+    refValue() -= n*(n & refValue());
+
+    // Lookup the momentum transport model
+    const momentumTransportModel& transportModel =
+        db().lookupType<momentumTransportModel>();
+
+    // Get the patch laminar viscosity
+    const tmp<scalarField> nuEff(transportModel.nuEff(patch().index()));
+
+    // Calculate the drag coefficient from the drag constant
+    // and the magnitude of the velocity difference
+    const scalarField Ds(Cs_*mag(refValue() - *this));
+
+    // Calculate the value-fraction from the balance between the
+    // external fluid drag and internal film stress
+    valueFraction() = Ds/(Ds + patch().deltaCoeffs()*nuEff);
+
+    mixedFvPatchField<vector>::updateCoeffs();
+
+    // Restore tag
+    UPstream::msgType() = oldTag;
+}
+
+
+void Foam::filmSurfaceVelocityFvPatchVectorField::write
+(
+    Ostream& os
+) const
+{
+    fvPatchField<vector>::write(os);
+
+    writeEntry(os, "Cs", Cs_);
+    writeEntry(os, "value", *this);
+}
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+   makePatchTypeField
+   (
+       fvPatchVectorField,
+       filmSurfaceVelocityFvPatchVectorField
+   );
+}
+
+
+// ************************************************************************* //
diff --git a/applications/solvers/modules/isothermalFilm/derivedFvPatchFields/filmSurfaceVelocity/filmSurfaceVelocityFvPatchVectorField.H b/applications/solvers/modules/isothermalFilm/derivedFvPatchFields/filmSurfaceVelocity/filmSurfaceVelocityFvPatchVectorField.H
new file mode 100644
index 0000000000..1f4e93a6be
--- /dev/null
+++ b/applications/solvers/modules/isothermalFilm/derivedFvPatchFields/filmSurfaceVelocity/filmSurfaceVelocityFvPatchVectorField.H
@@ -0,0 +1,165 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Copyright (C) 2023 OpenFOAM Foundation
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Class
+    Foam::filmSurfaceVelocityFvPatchVectorField
+
+Description
+    Film surface velocity boundary condition
+
+    Evaluates the surface velocity from the shear imposed by the neighbouring
+    fluid velocity using a simple drag model based on the difference between the
+    fluid and film velocities multiplied by the coefficient \c Cs.  This simple
+    model is used in preference to the standard viscous shear stress model in
+    order to provide some means to include the drag enhancing effect
+    of surface ripples, rivulets etc. in the film surface.
+
+Usage
+    \table
+        Property     | Description             | Required    | Default value
+        Cs           | Fluid-film drag coefficient | yes |
+    \endtable
+
+    Example of the boundary condition specification:
+    \verbatim
+    <patchName>
+    {
+        type            filmSurfaceVelocity;
+        Cs              0.005;
+    }
+    \endverbatim
+
+See also
+    Foam::mixedFvPatchField
+
+SourceFiles
+    filmSurfaceVelocityFvPatchVectorField.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef filmSurfaceVelocityFvPatchVectorField_H
+#define filmSurfaceVelocityFvPatchVectorField_H
+
+#include "mixedFvPatchFields.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+/*---------------------------------------------------------------------------*\
+          Class filmSurfaceVelocityFvPatchVectorField Declaration
+\*---------------------------------------------------------------------------*/
+
+class filmSurfaceVelocityFvPatchVectorField
+:
+    public mixedFvPatchVectorField
+{
+    // Private Data
+
+        //- Fluid-film drag-coefficient
+        scalar Cs_;
+
+
+public:
+
+   //- Runtime type information
+   TypeName("filmSurfaceVelocity");
+
+
+   // Constructors
+
+        //- Construct from patch and internal field
+        filmSurfaceVelocityFvPatchVectorField
+        (
+            const fvPatch&,
+            const DimensionedField<vector, volMesh>&
+        );
+
+        //- Construct from patch, internal field and dictionary
+        filmSurfaceVelocityFvPatchVectorField
+        (
+            const fvPatch&,
+            const DimensionedField<vector, volMesh>&,
+            const dictionary&
+        );
+
+        //- Construct by mapping given
+        //  filmSurfaceVelocityFvPatchVectorField
+        //  onto a new patch
+        filmSurfaceVelocityFvPatchVectorField
+        (
+            const filmSurfaceVelocityFvPatchVectorField&,
+            const fvPatch&,
+            const DimensionedField<vector, volMesh>&,
+            const fvPatchFieldMapper&
+        );
+
+        //- Disallow copy without setting internal field reference
+        filmSurfaceVelocityFvPatchVectorField
+        (
+            const filmSurfaceVelocityFvPatchVectorField&
+        ) = delete;
+
+        //- Copy constructor setting internal field reference
+        filmSurfaceVelocityFvPatchVectorField
+        (
+            const filmSurfaceVelocityFvPatchVectorField&,
+            const DimensionedField<vector, volMesh>&
+        );
+
+        //- Construct and return a clone setting internal field reference
+        virtual tmp<fvPatchVectorField> clone
+        (
+            const DimensionedField<vector, volMesh>& iF
+        ) const
+        {
+            return tmp<fvPatchVectorField>
+            (
+                new filmSurfaceVelocityFvPatchVectorField
+                (
+                    *this,
+                    iF
+                )
+            );
+        }
+
+
+    // Member Functions
+
+        //- Update the coefficients associated with the patch field
+        virtual void updateCoeffs();
+
+        //- Write
+        virtual void write(Ostream&) const;
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //
diff --git a/src/MomentumTransportModels/momentumTransportModels/derivedFvPatchFields/fixedShearStress/fixedShearStressFvPatchVectorField.C b/src/MomentumTransportModels/momentumTransportModels/derivedFvPatchFields/fixedShearStress/fixedShearStressFvPatchVectorField.C
index 6c526be65e..c4a02db0d2 100644
--- a/src/MomentumTransportModels/momentumTransportModels/derivedFvPatchFields/fixedShearStress/fixedShearStressFvPatchVectorField.C
+++ b/src/MomentumTransportModels/momentumTransportModels/derivedFvPatchFields/fixedShearStress/fixedShearStressFvPatchVectorField.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
@@ -93,7 +93,7 @@ void Foam::fixedShearStressFvPatchVectorField::updateCoeffs()
     const momentumTransportModel& turbModel =
         db().lookupType<momentumTransportModel>(internalField().group());
 
-    scalarField nuEff(turbModel.nuEff(patch().index()));
+    const scalarField nuEff(turbModel.nuEff(patch().index()));
 
     const vectorField Uc(patchInternalField());