Abstract
Studying the movement of fluid requires some assumptions about how fluid flows (the boundary condition) at the solid-fluid interface. The boundary condition, commonly known as the no-slip condition, states that fluid elements adjacent to a surface assume its velocity. Despite its remarkable success in replicating the characteristics of many flow types, this condition can produce unusual or singular behavior when applied to the spreading of a fluid on a solid substrate, corner flow, and forcing molten polymers out of a narrow tube. Maxwell and Navier’s slip model resolved these difficulties by allowing finite slip at liquid-solid interfaces. However, these phenomenological models cannot provide a universal perception of momentum transfer at liquid-solid interfaces. Thompson and Troian showed that for high shear rates, the slip is no longer a constant rather, it is a function of the shear rate. This was further extended by Thalakkottor and Mohseni, who showed slip length is more generally a function of the principal strain rate. Both these models were validated using molecular dynamics simulations of a monoatomic liquid similar to liquid Argon, which is rarely encountered in real-world applications. In this study, we simulate water instead, using the TIP3P model. Three different liquid-solid interfaces with varying degrees of hydrophobicity are studied. The study demonstrates that the nonlinear slip model, especially Thompson and Troian’s slip model, is valid for water flows as well.
