LBE dimensionless

Hi guys,
I am a newcome for the LBE. And i can not understand so much about the LBE unit.
According to the paper,(lattice Boltzmann simulation of lid-driven flow in deep cavities 2006 D.V. Patil), we use the dimensionless form, the individual quantities u_{lb}=u_{p}/(dx_{p}/dt_{p}) x_{lb}=x_{p}/dx_{p} t_{lb}=t_{p}/dt_{p} nu_{lb}=miu_{p}*dt_{p}/dx^2_{p} dx_{p}=x_ref/N
where dx_{p}=x_ref/N stands for the lattice spaceing,
the N stands for the lattice units in one side,
the x_ref stands for the reference length.
Why we can use this kind of dimensionless method? What is the purpose of doing like this? It is similar to traditional CFD method? Where can i get the detailed introduction to this dimensionless method?
Thank you for your kind help

Best regards,