Yes, absolutely you can. But Why? Would it make a difference for you?

A simple length scale can be the smallest size of the grid. Another one can be the average size of the grid in the whole domain. I guess the main question here is why would you need to do such thing and for what problem?

Cheers

I am supposed to constuct a round active turbulence grid and so far what I read in papers the turbulence intensity after a certain distance correlates always with the turbulence lenght scale (Kolmogorv).

Are you referring to integral leght scale or to the Kolmogorov scale??

The integral lenght scale.