Question

According to reynolds the critical velocity for fluid in a tube is

Answer 1

Answer:

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,

.....................................................(1)

where is the Reynold Number.

The above expression can also be obtained by dimensional analysis,

i.e.

.....................(2)

From equ(2), we can arrive at, a = 1, b = -1 and c = -1

i.e., or

The critical number appears as a proportional constant. from equ(1), one can infer that the liquid of higher viscosity and lower density promotes steady state flow. The steady state flow can also be obtained with ease using narrow tubes, i.e., with smaller 'r' values. As per experiments, for values less than 1000, the fluids are under steady state flow.