# Reynolds Number

In 1883, Osborne Reynold proved experimentally that in case of viscous liquid, critical velocity is given by

V_{c} =

Where D is diameter of tube, η coefficient of viscosity of liquid, ρ its density and N is a number, called Reynoldâ€™s number. From equations we have

N =

**Discussion of the results**

- From the above equation it follows that for a liquid having large value of coefficient of viscosity, low value of density and flowing through a tube of narrow bore, the value of critical velocity may be too large to be possessed by the liquid. Hence, such a liquid will possess streamlined flow.
- On the other hand, for a liquid having low value of coefficient of viscosity, large value of density and flowing through a tube of wide bore, the value of critical velocity will be very low. As this velocity can be easily attained by the liquid, the motion of such a liquid would be turbulent in nature.