Hybrid Atomistic–Continuum Formulationsand the Moving Contact-Line Problem

We present a hybrid atomistic–continuum computational framework for the treatment of dense fluid problems with emphasis on the coupling of molecular dynamics with continuum (finite element/spectral) methods for problems involving multi-fluid dynamics in the presence of multi-fluid interfaces. The technique is an extension of the single-fluid framework already presented by the author. The well-known moving contact-line problem is used as a validation example. A hybrid solution that employs molecular dynamics close to the walls where molecular effects are important and continuum fluid mechanics in the remainder of the domain (far field region) is obtained. A fully molecular solution of the same problem serves as an exact solution. Various issues related to dense fluid atomistic–continuum techniques are discussed and contrasted to the already existing but less general dilute gas techniques. Numerical considerations are discussed with particular emphasis on efficiency, and a formulation that reduces computational cost is proposed. c © 1999 Academic Press