The squeeze flow of a bi-viscosity fluid between two rigid spheres with wall slip

In this paper,the squeeze flow between two rigid spheres with a bi-viscosity fluid is examined.Based on lubrication theory,the squeeze force is calculated by deriving the pressure and velocity expressions.The results of the normal squeeze force are discussed,and fitting functions of the squeeze and correction coefficients are given.The squeeze force between the rigid spheres increases linearly or logarithmically with the velocity when most or part of the boundary fluid reaches the yield state,respectively.Furthermore,the slip correction coefficient decreases with the increase in the velocity.The investigation may contribute to the further study of bi-viscosity fluids between rigid spheres with wall slip.