consistent numbering with postChannel tutorial

applications/utilities/postProcessing/miscellaneous/postChannel/postChannelDict

@@ -15,11 +15,13 @@ FoamFile
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
-Nx    40;
-Ny
-(
-    50
-);
-Nz    30;
+Nx 40; 
+Ny 
+( 
+ 25 
+ 25 
+); 
+Nz 30; 
+ 
 
 // ************************************************************************* //