What is Reynolds number? What is its importance?

Explanation

Reynold.s number
It is a pure number, whose value decides the nature of flow of the liquid through a pipe. ?
`R_(e)=(rhovd)/(eta)`
where `rho`= density of the liquid `impliesv=` velocity of the liquid
`eta`= coefficient of viscosity of the liquid
d = diameter of the pipe.
Importance of Reynold.s number
If `R_(e)` lies between 0 and 2000, the flow of liquid is streamlined. If `R_(e)` lies between 2000 and 3000, the flow of liquid is unstable i.e. it may change from laminar to turbulent and vice-versa. If `R_(e)` is greater than 3000, the flow of liquid is turbulent.