Verifying the validity of nonlinear slip for water under shear using molecular dynamics simulations.

To model fluid flows, certain assumptions about how the fluid moves past a surface (boundary condition) at the solid-fluid interface are necessary. A commonly used boundary condition is known as the "no-slip condition", which states that fluid elements adjacent to a surface adopt its velocity. While this condition has been successful in replicating the characteristics of many flow types, it can lead to unusual or singular behavior when applied to scenarios like spreading fluid on solid substrates or corner flow.

To address these issues, different boundary conditions have been explored, allowing for finite slip at the liquid-solid interfaces. However, these empirical models fail to offer a universal understanding of momentum transfer at fluid/solid interfaces. Initially, Thompson and Troian introduced a slip model showing that at high shear rates, slip is no longer constant but instead becomes a function of the shear rate. Their slip model was verified by performing molecular dynamics simulations of a Lennard-Jones (LJ) fluid. In this study, we verify the validity of their non-linear slip model for a real fluid, water (TIP3P).