There is no force model "totalMomentumExchange". There are some references in
the tutorials and the doxygen files. All references to "totalMomentumExchange" have
been removed from the tutorials.
There is no force model named "RongDrag", it is also not mentioned in the
documentation. Thus, it is safe to remove all references to it from the
tutorials.
Since OpenFOAM-3.0 it is the convention to put blockMeshDict into system
instead of constant/polyMesh
Having blockMeshDict in system is supported since OpenFOAM-2.3