Question

Derivation of critical velocity

Answer 1

 The critical velocity is the velocity of fluid at which turbulance sets in. Osborne Reynolds (1842-1912) showed that the critical velocity v for a fluid flowing through a narrow tube is a function of coefficient of viscosity density of the fluid and the radius 'r' of the tube. That is, 
                                   
(V)c =(R)c N/PR