At low Reynolds numbers, flows tend to be dominated by laminar (sheet-like) flow, while at high Reynolds numbers, flows tend to be turbulent. In fluid mechanics, the Reynolds number ( Re) is a dimensionless quantity that helps predict fluid flow patterns in different situations by measuring the ratio between inertial and viscous forces. Osborne Reynolds popularised the concept. George Stokes introduced Reynolds numbers.
This can occur around cylinders and spheres, for any fluid, cylinder size, and fluid speed provided that it has a Reynolds number between roughly. The transition from laminar (left) to turbulent (right) flow of water from a tap occurs as the Reynolds number increases.
