density in susp3d code

Hello everyone,

I am using the open source code susp3d. In this code density (in lattice unit of course) of fluid is set as 36. From my knowledge so far lattice system density is set up based on a reference density, i.e. density in physical unit= reference density * density in the lattice unit. Most of the time i observe that density in the lattice system is set as 1. Hence where could be this constant value (36) origin? By the way, it is the average value of density in the fluid as total density is expressed as the sum of average and fluctuating component´╝î

Thanks a lot!