A molecular dynamics simulation of TIP4P and Lennard-Jones water in nanochannel

The flow characteristics of the plane Poiseuille flow in the nanochannel driven by a constant external force are studied by the Lennard-Jones and TIP4P potentials. The problem is investigated by the leap-frog method in the field of molecular dynamics. In this work, the wall boundary condition is considered to be the situation that the water is absorbed on the metal wall and is then formed to be flat ice. Both global effect (effective channel width) and local effect (wall boundary types) are examined to demonstrate the features of the distributions of velocity and its gradient in the system. When the effective channel width is less than a critical value, the numerical results show that the Navier-Stokes theory would fail to predict the velocity distribution. Furthermore, the velocity profile at a virtual slip plane presents the slip condition. Finally, we can reason that the surface effect exists and will affect the shear stress in the nanochannel.