ENH: Adding FPE stabilization to Edash for nutkAtmRoughWall

src/turbulenceModels/incompressible/RAS/derivedFvPatchFields/wallFunctions/nutWallFunctions/nutkAtmRoughWallFunction/nutkAtmRoughWallFunctionFvPatchScalarField.C

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2011-2012 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2013 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -63,10 +63,10 @@ tmp<scalarField> nutkAtmRoughWallFunctionFvPatchScalarField::calcNut() const
         scalar uStar = Cmu25*sqrt(k[faceCellI]);
         scalar yPlus = uStar*y[faceI]/nuw[faceI];
 
-        scalar Edash = (y[faceI] + z0_[faceI])/z0_[faceI];
+        scalar Edash = (y[faceI] + z0_[faceI])/(z0_[faceI] + 1e-4);
 
         nutw[faceI] =
-            nuw[faceI]*(yPlus*kappa_/log(max(Edash, 1+1e-4)) - 1);
+            nuw[faceI]*(yPlus*kappa_/log(max(Edash, 1 + 1e-4)) - 1);
 
         if (debug)
         {