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International Journal for Multiscale Computational Engineering
IF: 1.016 5-Year IF: 1.194

ISSN Print: 1543-1649
ISSN Online: 1940-4352

International Journal for Multiscale Computational Engineering

DOI: 10.1615/IntJMultCompEng.v2.i2.20
15 pages

Discussion of Hybrid Atomistic-Continuum Methods for Multiscale Hydrodynamics

Hettithanthrige S. Wijesinghe
Mechanical Engineering Department, Massachusetts Institute of Technology, Cambridge, MA 02139
Nicolas G. Hadjiconstantinou
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA

ABSTRACT

We discuss hybrid atomistic-continuum methods for multiscale hydrodynamic applications. Both dense-fluid and dilute-gas formulations are considered. The choice of coupling method and its relation to the fluid physics as well as the need for timescale decoupling is highlighted. In particular, by relating the molecular integration timestep to the CFL timestep, we show that compressibility is important in determining the choice of a coupling method. Appropriate coupling techniques for various flow regimes are discussed and proposed. We also discuss recently developed incompressible and compressible hybrid methods for dilute gases. The incompressible framework is based on the Schwarz alternating method, which provides timescale decoupling; the compressible method is a multispecies, fully adaptive mesh and algorithm refinement approach that introduces the direct-simulation Monte Carlo at the finest level of mesh refinement.