diff --git a/src/finiteVolume/finiteVolume/ddtSchemes/localEulerDdtScheme/localEulerDdtScheme.H b/src/finiteVolume/finiteVolume/ddtSchemes/localEulerDdtScheme/localEulerDdtScheme.H
index c014ccb47c2e02cbe5cd337a6fb0076f1d49bc98..bb3f2187fe7c4c36fb385433be242625ab2a5eb5 100644
--- a/src/finiteVolume/finiteVolume/ddtSchemes/localEulerDdtScheme/localEulerDdtScheme.H
+++ b/src/finiteVolume/finiteVolume/ddtSchemes/localEulerDdtScheme/localEulerDdtScheme.H
@@ -131,19 +131,19 @@ public:
 
         tmp<fvMatrix<Type> > fvmDdt
         (
-            GeometricField<Type, fvPatchField, volMesh>&
+            const GeometricField<Type, fvPatchField, volMesh>&
         );
 
         tmp<fvMatrix<Type> > fvmDdt
         (
             const dimensionedScalar&,
-            GeometricField<Type, fvPatchField, volMesh>&
+            const GeometricField<Type, fvPatchField, volMesh>&
         );
 
         tmp<fvMatrix<Type> > fvmDdt
         (
             const volScalarField&,
-            GeometricField<Type, fvPatchField, volMesh>&
+            const GeometricField<Type, fvPatchField, volMesh>&
         );
 
         typedef typename ddtScheme<Type>::fluxFieldType fluxFieldType;