  In conventional fluid mechanics, the chemical composition and thermodynamic
state of a fluid-solid interface are not considered when establishing
velocity-field boundary conditions. As a consequence, fluid simulations are
usually not able to generate different outputs when interfacial materials are
varied. By considering an atomistic description of matter, theoretical
determination of material-specific boundary conditions becomes possible,
thereby providing an improved alternative to the completely-invariant no-slip
condition. Such a scheme constitutes a multiscale approach to fluid dynamics
involving essentially two transitions between space-time scales: the first
concerns the derivation of macroscopic boundary conditions by means of
molecular assessment of slip lengths; the second concerns the construction of
interatomic force fields, required by molecular dynamics simulations, from
quantum theory. In this introductory overview we discuss some of the
fundamental aspects of these problems.

Fluid Dynamics;Applied Physics;Computational Physics