The space between two square flat parallel plate is filled with oil. Each side of plate os 720 mm. The thickness of oil film is 15 mm. The upper plate which moves at 3 m/s requires a force of 120 N to maintain speed. Determine:

• dynamic viscosity of oil
• kinematic viscosity of oil if specific gravity of oil is 0.95

SOLUTION:

Given,

Each side of the square plate =720 mm = 0.72 m

Thickness of the oil film, `dy=15 mm=0.015 m`

Velocity of the upper plate, `du=3`m/s.

Force required on the upper plate; `F=120 N`

Dynamic viscosity, `mu=?`

Kinematic viscosity, `nu=?`

Now,we have,

`tau=mu*(du)/(dy)`

or, `mu=tau*(dy)/(du)`

`=F/A*(dy)/(du)`

`=120/(0.7....Show More

SOLUTION:

Given,

Each side of the square plate =720 mm = 0.72 m

Thickness of the oil film, `dy=15 mm=0.015 m`

Velocity of the upper plate, `du=3`m/s.

Force required on the upper plate; `F=120 N`

Dynamic viscosity, `mu=?`

Kinematic viscosity, `nu=?`

Now,we have,

`tau=mu*(du)/(dy)`

or, `mu=tau*(dy)/(du)`

`=F/A*(dy)/(du)`

`=120/(0.72\ *\ 0.72)*0.015/3`

Thus, `mu=1.16`Ns/`m^2` `=11.6`poise.

Also, we have,

Kinematic viscosity, `nu=mu/rho`

Also, specific gravity`=0.95=rho/1000`

Thus, `rho=950`kg/`m^3`

Thus,

`nu=1.16/950`$*$1.22$ *$`10^(-3) m^2/s`

`nu=12.21` stokes.