One of the observation made by O. Reynold in 1883 is
1
When the velocity of flow was low, the dye-filament in the glass tube was randomly distributed
2
With the increase of velocity of flow, the dye-filament was in the form of straight line
3
The straight line of dye filament parallel to the glass tube was the case of laminar flow
4
With further increase of velocity of flow, the dye-filament fails to produce shear stresses