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Sound waves, diffusive transport, and wall slip in nanoconfined compressible fluids

Holey, Hannes ORCID iD icon 1; Gumbsch, Peter 1; Pastewka, Lars
1 Institut für Angewandte Materialien (IAM), Karlsruher Institut für Technologie (KIT)

Abstract:

Although continuum theories have been proven quite robust to describe confined fluid flow at molecular length scales, molecular dynamics (MD) simulations reveal mechanistic insights into the interfacial dissipation processes. Most MD simulations of confined fluids
have used setups in which the lateral box size is not much larger than the gap height, thus breaking thin-film assumptions usually employed in continuum simulations. Here we explicitly probe the long-wavelength hydrodynamic correlations in confined simple fluids
with MD and compare to gap-averaged continuum theories as typically applied in, e.g., lubrication. Relaxation times obtained from equilibrium fluctuations interpolate between the theoretical limits from bulk hydrodynamics and continuum formulations with increasing
wavelength. We show how to exploit this characteristic transition to measure viscosity and slip length in confined systems simultaneously from equilibrium MD simulations. Moreover, the gap-averaged theory describes a geometry-induced dispersion relation that
leads to overdamped sound relaxation at large wavelengths, which is confirmed by our MD simulations. ... mehr


Verlagsausgabe §
DOI: 10.5445/IR/1000168649
Veröffentlicht am 23.02.2024
Cover der Publikation
Zugehörige Institution(en) am KIT KIT-Bibliothek (BIB)
Institut für Angewandte Materialien – Zuverlässigkeit und Mikrostruktur (IAM-ZM)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 01.2024
Sprache Englisch
Identifikator ISSN: 2469-990X, 2469-9918
KITopen-ID: 1000168649
Erschienen in Physical Review Fluids
Verlag American Physical Society (APS)
Band 9
Heft 1
Seiten Art.-Nr.: 014203
Vorab online veröffentlicht am 29.01.2024
Nachgewiesen in Dimensions
Web of Science
Scopus
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