Question

Water flows at a speed of 6 cm s^-1 through a tube of radius 1 cm. Coefficient of viscosity of water at room temperature is 0.01 poise. Calculate the Reynolds number. Is it a steady flow?

• A. 60, yes
• B. 60, no
• C. 120, yes
• D. 120, no

Answer 1

The correct option is C

120, yes

You know,
Reynolds number, $N=\frac{\rho vD}{\eta }$
Where, $\rho$ = density of fluid

v = velocity of flow of the fluid

D = diameter of the tube
$\eta$ = coefficient of viscosity of the fluid
$\Rightarrow N=\frac{1000\times \frac{6}{100}\times \frac{2}{100}}{0.01}$
{all values in SI}
N = 120 {Dimensionless}, yes the flow is steady