In a simple concentric shaft-bearing arrangement, the

In a simple concentric shaft-bearing arrangement, the lubricant flows in the 2 mm gap between the shaft and the bearing. The flow may be assumed to be a plane Couette flow with zero pressure gradient. The diameter of the shaft is 100 mm and its tangential speed is 10 m/s. The dynamic viscosity of the lubricant is 0.1 kg/ms. The frictional resisting force (in Newton) per 100 mm length of the bearing is

F = A × μ	du	=	πDμ[u_t - u_w]
	dr		(∆t)

u_t = tangential velocity
u_w = velocity at bearing

F = π × 0.1 × 0.1 ×	0.1[10 - 0]
	2 × 10^-3

F = 15.707 N.