Continuum explanation of the cause of slip at an interface

Slip can be interpreted as the inability of an interface to transfer information across it. In the case of velocity and thermal slip this corresponds to the lack of transfer of momentum and energy across the interface, respectively. Here, we attempt to provide a continuum explanation of the cause of this lack of tangential transfer of information. Using the results from molecular dynamics simulations we demonstrate that slip is analogous to a shock in fluid dynamics. Mathematically, slip can be considered as a change in the characteristic nature of the governing equation as one approaches a slipped wall. In the case of a shock there is a jump in the component of velocity normal to its plane, while in the case of slip this jump is in the component of velocity tangential to the interface.