diff --git a/tutorials/modules/incompressibleFluid/planarPoiseuille/validation/WatersKing/WatersKing.C b/tutorials/modules/incompressibleFluid/planarPoiseuille/validation/WatersKing/WatersKing.C
index 732d1479de..24330ca946 100644
--- a/tutorials/modules/incompressibleFluid/planarPoiseuille/validation/WatersKing/WatersKing.C
+++ b/tutorials/modules/incompressibleFluid/planarPoiseuille/validation/WatersKing/WatersKing.C
@@ -45,6 +45,7 @@ Description
 #include "fvCFD.H"
 #include "viscosityModel.H"
 #include "incompressibleMomentumTransportModel.H"
+#include "OFstream.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //