3. 4. A Couette viscometer consists essentially of two concentric cylinders of length L, the inner of which rotates while the outer is held stationary. Viscosity is determined by measuring the rate of rotation of the inner cylinder under application of a known torque. Develop an expression for the velocity field in this type of viscometer as a function of the applied torque for laminar flow of Newtonian liquids. Neglect end effects