Question

Problem 4 Two circular discs with radius 100mm are separated by a thin layer of thickness 0.5mm of SAE 20W oil which has a dynamic viscosity µ= 0.05 Ns/m2 at 400 C. The lower disc is held stationary while the upper disc rotates with angular velocity w = 30 rad/s. Determine the torque required to maintain the rotation rate. Assume the velocity profile across the gap is linear.

Answer 1