Question

The flow rate from a tap of diameter 1.25 cm is 3 lit/min. The coefficient of viscosity of water is ${10}^{-3}$ pas.The nature of flow is

• A. Turbulent
• B. Laminar
• C. Neither laminar or Turbulent
• D. Steady

Answer 1

The correct option is A Turbulent

Critical velocity is given by $v_c=\frac{k\eta }{\rho r}$

where k is reynold's number i.e 1000

putting values according to question : $v_c=0.16m/s$

$\text{When flow rate is}3L/min$

$Q^{\prime }=3L/min=\frac{3}{60}L/ml$

$=\frac{1}{20}\times {10}^{-3}{m}^3/sec$

$A=1.227\times {10}^{-4}$

$V_2=\frac{Q^{\prime }}{A}=\frac{1\times {10}^{-3}}{20\times 1.227\times {10}^{-4}}$

$V_2=\frac{1}{2\times 1.227}=0.40m/s$

$V_2>V_c\Rightarrow \text{turbulent flow}$

Hence option A is correct.