This is about the incompressible flow parameters (IncomprFlowParam) structure provided in units.h
I may be wrong but i think the formula for lattice NU is missing the physical velocity parameter.
Reason could be physical velocity is initialized to one (along with phy length) to facilitate the examples. But there is another constructor which allows a physical velocity other than 1 but it has not been considered later in this formula.
Thanks and sorry if i am wrong…