title: Relaxation of a steep density gradient in a simple fluid: comparison between atomistic and continuum modeling.
abstract: We compare dynamical nonequilibrium molecular dynamics and continuum simulations of the dynamics of relaxation of a fluid system characterized by a non-uniform density profile. Results match quite well as long as the lengthscale of density nonuniformities are greater than the molecular scale (~10 times the molecular size). In presence of molecular scale features some of the continuum fields (e.g., density and momentum) are in good agreement with atomistic counterparts, but are smoother. On the contrary, other fields, such as the temperature field, present very large difference with respect to reference (atomistic) ones. This is due to the limited accuracy of some of the empirical relations used in continuum models, the equation of state of the fluid in the present example.
authors.affiliation: Department of Physical Chemistry, School of Chemistry, College of Science, University of Tehran, Tehran, Iran.
authors.forename: Meisam
authors.initials: M
authors.lastname: Pourali
authors.affiliation: Laboratory of Computational Chemistry and Biochemistry, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Simone
authors.initials: S
authors.lastname: Meloni
authors.affiliation: Dipartimento di Ingegneria Meccanica e Aerospaziale, Università La Sapienza, Via Eudossiana 18, 00184 Rome, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Magaletti
authors.affiliation: Department of Physical Chemistry, School of Chemistry, College of Science, University of Tehran, Tehran, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Maghari
authors.affiliation: Dipartimento di Ingegneria Meccanica e Aerospaziale, Università La Sapienza, Via Eudossiana 18, 00184 Rome, Italy.
authors.forename: Carlo Massimo
authors.initials: CM
authors.lastname: Casciola
authors.affiliation: Dipartimento di Fisica and CNISM, Università La Sapienza, P.le A. Moro 5, 00185 Rome, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Ciccotti