volume-coupled-flow: add y and z components in source term (#544)

Author: MakisH

changelog-entries/544.md

@@ -0,0 +1 @@
+- Fixed the [volume-coupled flow tutorial](https://precice.org/tutorials-volume-coupled-flow.html) to correctly assign all components of the read velocity field.

volume-coupled-flow/fluid-openfoam/constant/fvOptions

@@ -27,6 +27,8 @@ codedSource
         for(auto cell : cells)
         {
             fld[cell].x() = U_vol[cell].x();
+            fld[cell].y() = U_vol[cell].y();
+            fld[cell].z() = U_vol[cell].z();
         }
     #};
 
@@ -39,4 +41,4 @@ codedSource
     #{
         return;
     #};
-}
+}