diff --git a/applications/solvers/modules/isothermalFilm/derivedFvPatchFields/filmSurfaceVelocity/filmSurfaceVelocityFvPatchVectorField.C b/applications/solvers/modules/isothermalFilm/derivedFvPatchFields/filmSurfaceVelocity/filmSurfaceVelocityFvPatchVectorField.C
index 4a7296ebcd..6b874aedeb 100644
--- a/applications/solvers/modules/isothermalFilm/derivedFvPatchFields/filmSurfaceVelocity/filmSurfaceVelocityFvPatchVectorField.C
+++ b/applications/solvers/modules/isothermalFilm/derivedFvPatchFields/filmSurfaceVelocity/filmSurfaceVelocityFvPatchVectorField.C
@@ -55,7 +55,7 @@ filmSurfaceVelocityFvPatchVectorField
 )
 :
     mixedFvPatchField<vector>(p, iF, dict, false),
-    Cs_(dict.lookup<scalar>("Cs"))
+    Cs_(dict.lookupOrDefault<scalar>("Cs", 0))
 {
     refValue() = Zero;
     refGrad() = Zero;
@@ -139,16 +139,41 @@ void Foam::filmSurfaceVelocityFvPatchVectorField::updateCoeffs()
     const momentumTransportModel& transportModel =
         db().lookupType<momentumTransportModel>();
 
-    // Get the patch laminar viscosity
-    const tmp<scalarField> nuEff(transportModel.nuEff(patch().index()));
+    // Get the patch laminar viscosity divided by delta
+    const tmp<scalarField> nuEffByDelta
+    (
+        transportModel.nuEff(patch().index())*patch().deltaCoeffs()
+    );
 
-    // Calculate the drag coefficient from the drag constant
-    // and the magnitude of the velocity difference
-    const scalarField Ds(Cs_*mag(refValue() - *this));
+    if (Cs_ > 0)
+    {
+        // 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);
+        // Calculate the value-fraction from the balance between the
+        // external fluid drag and internal film stress
+        valueFraction() = Ds/(Ds + nuEffByDelta);
+    }
+    else
+    {
+        // Lookup the neighbour momentum transport model
+        const momentumTransportModel& transportModelNbr =
+            mpp.nbrMesh().lookupType<momentumTransportModel>();
+
+        // Get the patch laminar viscosity
+        const tmp<scalarField> nuEffByDeltaNbr
+        (
+            mpp.distribute
+            (
+                transportModelNbr.nuEff(patchiNbr)*patchNbr.deltaCoeffs()
+            )
+        );
+
+        // Calculate the value-fraction from the balance between the
+        // external fluid and internal film stresses
+        valueFraction() = nuEffByDeltaNbr()/(nuEffByDelta + nuEffByDeltaNbr());
+    }
 
     mixedFvPatchField<vector>::updateCoeffs();
 
@@ -163,7 +188,12 @@ void Foam::filmSurfaceVelocityFvPatchVectorField::write
 ) const
 {
     fvPatchField<vector>::write(os);
-    writeEntry(os, "Cs", Cs_);
+
+    if (Cs_ > 0)
+    {
+        writeEntry(os, "Cs", Cs_);
+    }
+
     writeEntry(os, "value", *this);
 }
 
diff --git a/applications/solvers/modules/isothermalFilm/derivedFvPatchFields/filmSurfaceVelocity/filmSurfaceVelocityFvPatchVectorField.H b/applications/solvers/modules/isothermalFilm/derivedFvPatchFields/filmSurfaceVelocity/filmSurfaceVelocityFvPatchVectorField.H
index 1f4e93a6be..256ddb23c5 100644
--- a/applications/solvers/modules/isothermalFilm/derivedFvPatchFields/filmSurfaceVelocity/filmSurfaceVelocityFvPatchVectorField.H
+++ b/applications/solvers/modules/isothermalFilm/derivedFvPatchFields/filmSurfaceVelocity/filmSurfaceVelocityFvPatchVectorField.H
@@ -28,24 +28,36 @@ 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.
+    fluid velocity using either a simple drag model based on the difference
+    between the fluid and film velocities multiplied by the coefficient \c Cs or
+    if \c Cs is not specified or set to 0 the fluid viscous shear stress.
+
+    The simple model might be used in preference to the fluid 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 |
+        Cs           | Fluid-film drag coefficient | no | 0
     \endtable
 
-    Example of the boundary condition specification:
+    Example of the boundary condition specification using the simple drag model:
     \verbatim
     <patchName>
     {
         type            filmSurfaceVelocity;
         Cs              0.005;
+        value           $internalField;
+    }
+    \endverbatim
+
+    Example of the boundary condition specification using the fluid stress:
+    \verbatim
+    <patchName>
+    {
+        type            filmSurfaceVelocity;
+        value           $internalField;
     }
     \endverbatim