Question

the mean velocity of a laminar flow through a circular pipe of 30 cm is 15m/s. the local velocity of the flow at a radius of 25 cm is

Answer 1

35m/s

the mean velocity of laminar is 35m/s

Answer 2

Answer:9.16 m/s

Explanation:

Given

$v_{mean}=15 m/s$

radius of circular pipe R=30 cm

velocity at r=25 cm

and we know $v(r)=v_{max}\left [ 1-\left ( \frac{r}{R}\right )^2\right ]$

In laminar flow $\frac{v_{max}}{v_{mean}}=2$

Therefore $v_{max}=2\times 15=30 m/s$

Thus $v(r=25)=30\times \left [ 1-\left ( \frac{25}{30}\right )^2\right ]$

$v(r=25)=9.16 m/s$