Wall slip effect on the squeeze flow of a viscoelastic fluid confined between two parallel disks or between a sphere and a disk

Squeeze flow refers to the fluid flow between two parallel or near-parallel surfaces that converge toward each other, allowing the fluid to move relative to the surface. This phenomenon is important in various applications, including lubrication systems, biological systems, and microfluidic devices, where conventional no-slip boundary conditions are not always valid, especially at small scales. This study examines the effect of wall slip on the squeeze flow behavior of an upper-convected Maxwell fluid confined between two parallel disks or between a sphere and a disk. The lubrication approximation is used to obtain the expressions for the pressure distribution and the normal squeeze force in the disk–disk configuration. The introduction of slip changes the flow dynamics, reducing viscous resistance and allowing faster fluid drainage between the surfaces. Furthermore, this analysis is extended to a sphere-disk configuration. The effects of wall slip on the pressure distribution, film thickness, and flow rate are analyzed. The key findings suggest that slip has a major impact on flow behavior in areas with high shear and tight spaces. In general, wall slip improves the lubrication efficiency and could lead to new engineering applications in nanofluidics and soft materials.