Force & Viscosity between two parallel plates

AI Thread Summary
The discussion revolves around calculating the torque required to rotate a flat circular disc over a fixed surface, separated by an oil film. The viscosity of the oil is significantly higher than that of water, and the gap between the disc and surface is 0.5mm. The user initially attempts to apply the shear force equation but struggles with converting angular velocity into shear force and torque. After some calculations, the user arrives at a torque value of 2.05 N*m. The final answer indicates a successful resolution of the problem.
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Homework Statement


A flat circular disc of radius 1.0m is rotated at an angular velocity of 0.65 rad/sec over a fixed flat surface. An oil film separates the disk and the surface. If the viscosity of the oil is 16 times that of water (20 degree C) and the space between the disk and the fixed surface is 0.5mm, what is the torque required to rotate the disk?

Homework Equations



(T/A) = viscosity(dv/dy)

Where,
T= Shear Force
A= Area of the plate
v= velocity
y= gap between plates

The Attempt at a Solution



A= pi(0.5)^2= 0.7854 m^2
v= 0.65 rad/sec
y= 5e-4 m
Viscosity = 16(1.002e-3) = 16.032e-3 N*sec/m^2

How do I turn the rad/sec into shear force and thus torque?

Solving I get T = (0.7854)(16.032e-3)(0.65/5e-4) = 16.37 N*Rad/m

I'm at a loss from here.
 
Last edited:
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Nevermind, I've got it figured out. I went about it completely wrong. The answer I have now is 2.05 N*m.
 
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