diff --git a/src/finiteVolume/cfdTools/incompressible/CourantNo.H b/src/finiteVolume/cfdTools/incompressible/CourantNo.H
index b1e05b72a..b4c6ae2a2 100644
--- a/src/finiteVolume/cfdTools/incompressible/CourantNo.H
+++ b/src/finiteVolume/cfdTools/incompressible/CourantNo.H
@@ -61,7 +61,11 @@ else
 
     const scalar deltaX = Foam::cbrt(mesh.V()[0]);
 
-    velMag = mag(U[0]);
+    // recover velocity field in a more general way
+    const volVectorField& URef
+	    = mesh.db().lookupObject<const volVectorField>("U");
+
+    velMag = mag(URef[0]);
 
     CoNum = velMag*deltaT/deltaX;