Multiscale simulation of nanodrop over surfaces with varying hydrophilicity

•Adiabatic two-phase multiscale solver is developed by coupling FVM and MD.•Domain decomposition is used with boundary force model for missing molecules.•Drop dynamics due to varying hydrophilicity is demonstated using multiscale solver.•Usefulness of multiscale for reducing computational time than MD is established. Macroscale solvers primarily depend on empirical constitutive relations, which curbs their applicability and reliability. On the other hand, though the microscale solver is much more accurate, it cannot be used for engineering scale domains because of the high computational cost. As an alternative, in the present study, a new adiabatic two-phase multiscale solver has been developed by coupling Finite volume and molecular dynamics solvers with the help of the domain decomposition method. Due to the finiteness of the molecular subdomain, molecules near the boundary miss forces from the missing molecules. An effort has been made to develop a new boundary force model which mimics the effect of those missing molecules. The spreading of a drop has been simulated over surfaces with varying hydrophilicity using the solver and compared with the result of full molecular dynamics simulation. Further, the computational time has been compared with the full molecular dynamics simulation for different drop sizes to show the usefulness of the developed model. Drop translation over biphilic surfaces has also been simulated with the new solver.