Question

A piston having a diameter of 5.48 inches and a length of 9.50 in slides downward with a

velocity, V, through a vertical pipe. The downward motion is resisted by an oil film between
the piston and the pipe wall. The film thickness is 0.002 inches and the cylinder weighs 0.5
lb. Compute the velocity, V if the oil viscosity is 0.016 lb*s/ft
2
. Assume the velocity
distribution in the gap is linear. (answer: 0.0046 ft/sec)

Answer 1

`V = 4.585 * 10^(-3)  ft/s`

Step-by-step explanation:

surface Area is given as
`= \pi dL`

here , d is diameter of piston

L is distance travelled by the piston

`a = \pi 5.48* 9.5`

velocity of piston

`W = \mu A (V)/(t)`

where,

w is weight of piston,
`\mu` dynamic viscosity of fluid, t is thickness of fluid

`0.5 = 0.016 * (163.55)/(12^2) (V)/((0.002)/(12))`

`0.5 = 109.033 V`

SOLVING FOR V

`V = 4.585 * 10^(-3)  ft/s`