diff --git a/src/finiteVolume/fields/fvPatchFields/derived/movingWallVelocity/movingWallVelocityFvPatchVectorField.C b/src/finiteVolume/fields/fvPatchFields/derived/movingWallVelocity/movingWallVelocityFvPatchVectorField.C
index 1592f3f382..7a9c170d7a 100644
--- a/src/finiteVolume/fields/fvPatchFields/derived/movingWallVelocity/movingWallVelocityFvPatchVectorField.C
+++ b/src/finiteVolume/fields/fvPatchFields/derived/movingWallVelocity/movingWallVelocityFvPatchVectorField.C
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
+    Copyright (C) 2021 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -92,6 +93,38 @@ movingWallVelocityFvPatchVectorField
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
+Foam::tmp<Foam::vectorField>
+Foam::movingWallVelocityFvPatchVectorField::Uwall() const
+{
+    const fvMesh& mesh = internalField().mesh();
+    const fvPatch& p = patch();
+    const polyPatch& pp = p.patch();
+    const pointField& oldPoints = mesh.oldPoints();
+
+    vectorField oldFc(pp.size());
+
+    forAll(oldFc, i)
+    {
+        oldFc[i] = pp[i].centre(oldPoints);
+    }
+
+    const scalar deltaT = mesh.time().deltaTValue();
+
+    const vectorField Up((pp.faceCentres() - oldFc)/deltaT);
+
+    const auto& U = static_cast<const volVectorField&>(internalField());
+
+    tmp<scalarField> phip =
+        p.patchField<surfaceScalarField, scalar>(fvc::meshPhi(U));
+
+    const vectorField n(p.nf());
+    const scalarField& magSf = p.magSf();
+    tmp<scalarField> Un = phip/(magSf + VSMALL);
+
+    return (Up + n*(Un - (n & Up)));
+}
+
+
 void Foam::movingWallVelocityFvPatchVectorField::updateCoeffs()
 {
     if (updated())
@@ -103,35 +136,7 @@ void Foam::movingWallVelocityFvPatchVectorField::updateCoeffs()
 
     if (mesh.moving())
     {
-        const fvPatch& p = patch();
-        const polyPatch& pp = p.patch();
-        const pointField& oldPoints = mesh.oldPoints();
-
-        vectorField oldFc(pp.size());
-
-        forAll(oldFc, i)
-        {
-            oldFc[i] = pp[i].centre(oldPoints);
-        }
-
-        const scalar deltaT = mesh.time().deltaTValue();
-
-        const vectorField Up((pp.faceCentres() - oldFc)/deltaT);
-
-        const volVectorField& U =
-            static_cast<const volVectorField&>(internalField());
-
-        scalarField phip
-        (
-            p.patchField<surfaceScalarField, scalar>(fvc::meshPhi(U))
-        );
-
-        const vectorField n(p.nf());
-        const scalarField& magSf = p.magSf();
-        tmp<scalarField> Un = phip/(magSf + VSMALL);
-
-
-        vectorField::operator=(Up + n*(Un - (n & Up)));
+        vectorField::operator=(Uwall()());
     }
 
     fixedValueFvPatchVectorField::updateCoeffs();
diff --git a/src/finiteVolume/fields/fvPatchFields/derived/movingWallVelocity/movingWallVelocityFvPatchVectorField.H b/src/finiteVolume/fields/fvPatchFields/derived/movingWallVelocity/movingWallVelocityFvPatchVectorField.H
index bd272e9317..9b5b05cd7e 100644
--- a/src/finiteVolume/fields/fvPatchFields/derived/movingWallVelocity/movingWallVelocityFvPatchVectorField.H
+++ b/src/finiteVolume/fields/fvPatchFields/derived/movingWallVelocity/movingWallVelocityFvPatchVectorField.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2015 OpenCFD Ltd.
+    Copyright (C) 2015-2021 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -71,7 +71,6 @@ class movingWallVelocityFvPatchVectorField
 :
     public fixedValueFvPatchVectorField
 {
-
 public:
 
     //- Runtime type information
@@ -140,7 +139,10 @@ public:
         }
 
 
-    // Member functions
+    // Member Functions
+
+        //- Return wall velocity field
+        tmp<vectorField> Uwall() const;
 
         //- Update the coefficients associated with the patch field
         virtual void updateCoeffs();