Thus the dynamic viscosity of water is higher than that of air, in keeping with our intuitive notion. While the transition from laminar to turbulent flow occurs at a Reynolds number of approximately 2300 in a pipe, the precise value depends on whether any small disturbances are present. However, if Re is less than 2300, the flow will be laminar even if it is disturbed. Thus 2300 is the value the Re below which turbulence will not occur in a pipe. Moreover, if the flow has a different geometry, such as flow in a square duct, or over a turbine blade, transition will occur at different values of Re.
Air motion is invariably turbulent.
There is no such thing as a laminar smokestack. Clouds too are usually turbulent. Here we determine the Reynolds number using an approximate characteristic dimension of the cloud such as its height or width. A high value indeed. When the flow is turbulent, the flow contains eddying motions of all sizes, and a large part of the mechanical energy in the flow goes into the formation of these eddies which eventually dissipate their energy as heat.