Drop movements and replacement on surface driven by shear force via hybrid atomistic–continuum simulations

Abstract The movements and replacement of a nanoscale drop on a horizontal surface driven by shear force from the other immiscible fluid have been investigated by hybrid atomistic–continuum modelling in this work. The interfacial interaction near the drop, which may not be fully covered by the continuum theories, is modelled by molecular dynamics for accurate capture of transport behaviour, while the bulk flow region is simulated by the lattice Boltzmann method for high efficiency. The momentum exchange between atomistic and continuum regions is realised in a buffer region to couple the multiscale effects, where we propose an artificial solid molecular layer at the outer edge of buffer region to ensure the continuity of shear force between different regions. The influences of moving wall velocity, drop size, surface tension on resistance are examined. Our results show that the resistances increase with the moving wall velocity. A larger drop leads to a larger resistance to drop moving on solid wall, and a larger resistance to bulk flow. A higher surface tension results in a higher resistance to drop movement and bulk flow resistance over the drop because of lower deformation of drop.