Reply To: Changing resolution
using a constant relaxation time while changing the resolution results in changing the lattice velocity as well. These parameters are not independent. However, the Reynolds number is 20 for both cases. So, you should see similar simulation results for both cases. Keep in mind that changing the discretization will also change corresponding discretization errors.
For a good write up of the dimensionalization of the lattice boltzmann equation, have a look in the book by Krüger et al., chapter 7 (https://www.springer.com/de/book/9783319446479).