Question

A flow of liquid is streamline if the Reynolds number is

• A. greater than 1000
• B. between 4000 to 5000
• C. less than 1000
• D. between 2000 to 3000

Answer 1

Answer: (C)

less than 1000

Answer 2

Reynold's number is a pure number and it is equal to the ratio of the inertial force per unit area to the viscous force per unit area for a flowing fluid. Reynold's number $K=\frac{v_{c} \cdot \rho \cdot r}{\eta}$ where $\rho=$ density of the liquid $v_{c}=$ critical velocity $\eta=$ coefficient of viscosity of liquid $r=$ radius of capillary tube (i) For pure water flowing in a cylindrical pipe, $K$ is about 1000 . When $0 < K< 2000$, the flow of liquid is streamlined. (ii) When $2000< K< 3000$, the flow of liquid is variable between streamlined and turbulent. (iii) When $K >3000$, the flow of liquid is turbulent.