Squeeze flow of a power-law fluid between non-parallel plates

Squeeze flow in the gap between non-parallel circular plates of radius R is discussed. The test material is assumed to be a power-law fluid, with a no-slip boundary condition at the plates. If the mean separation between the plates is h, and the angle of inclination between the plates is ϕ ≪ h/R, the force on the plates is perturbed only at O(ϕ2) and is increased by less than 10% if ϕ < 0.35h/R. A torque O(ϕ) tends to return the plates to a parallel configuration.