The size of the largest eddies in turbulent flow, denoted by $L$, is set by that of the system boundary, such as pipe diameter or boundary layer thickness. Its relationship with the size of the dissipative eddies is expressed as $$ \frac{L}{\eta} \sim Re_L^{3/4} $$ For a flow with a given geometry, this formula states that the higher the Reynolds number, the smaller the size of the dissipative eddies

In other words, the flow at high Reynolds numbers covers a wider range of spatial scales. When the Reynolds number is small, the sizes of the large and small eddies are similar. In this case, the kinetic energy begins to dissipate in the large eddies, and the transportation process of energy cannot form. This type of flow is a laminar flow with eddies, rather than a turbulent flow