Fluid Mechanics Viscosity Question 124
Question: A viscous fluid is flowing through a cylindrical tube. The velocity distribution of the fluid is best represented by the diagram[BCECE 2005]
Options:
A) $ 4Q $
B) Q
C) $ \frac{Q}{4} $
D) $ \frac{Q}{8} $
Show Answer
Answer:
Correct Answer: D
Solution:
$ V=\frac{\pi pr^{4}}{8\eta l} $ $ V\propto P,r^{4} $ ($ \eta \ \text{and }l $ are constants) \ $ \frac{V_{2}}{V_{1}}=\left( \frac{P_{2}}{P_{1}} \right)\ {{\left( \frac{r_{2}}{r_{1}} \right)}^{4}} $ = $ 2\times {{\left( \frac{1}{2} \right)}^{4}} $ = $ \frac{1}{8} $ \ $ V_{2}=\frac{Q}{8} $