You asked over there why they can't depend on geometry and I think there might be two ways to look at this First: One large eddy becomes two smaller ones, which although become two smaller ones and so on until they dissipate When looking at it this way then you have this giant room (the largest eddies have been in it) and all of it is full of small eddies... 99% of them are far away from any geometric boundary Second: Again one large eddy becomes two smaller ones. The geometric boundaries played a major role for the large eddie, and is a little less important for the two smaller ones.. however they will strongly effect each other. When they become two smaller ones this effect becomes bigger. At the end you have this ton of small eddies, statistically distributed that are only effected by each other and the geomtry of the beginning does not play a role anymore.