2026-04-22T20:29:47Z https://archive.materialscloud.org/oai2d

oai:materialscloud.org:ybgqt-ewh55 2026-01-12T15:42:06Z openaire_data community-mcarchive

Cajahuaringa, Samuel Cajahuaringa, Samuel Bidoggia, Davide Peressi, Maria Marrazzo, Antimo 2026-01-12 <p>In rarefied atmospheric environments, where continuum fluid dynamics breaks down, aerodynamic drag is governed by gas–surface momentum exchange, making surface structure and chemistry key design knobs. Using molecular dynamics simulations, we show that coating the α-Al<sub>2</sub>O<sub>3</sub>(0001) surface with graphene markedly reduces the tangential momentum accommodation coefficient (TMAC) of N<sub>2</sub>, shifting scattering toward more specular reflection and thereby lowering drag; we further benchmark this response against graphite. The reduction is robust and strengthens up to 900 K. While structural defects can increase TMAC <em>–</em> and hence drag <em>–</em> via defect-induced corrugation and local atomic and electronic rearrangements, graphene retains near-ideal low-TMAC performance at experimentally relevant defect densities. These results identify graphene as a thermally resilient, low-drag coating for aerospace-relevant surfaces in rarefied flows.</p> text/x-python application/gzip text/markdown application/gzip text/markdown application/gzip application/gzip text/plain https://doi.org/10.24435/materialscloud:cq-rs oai:materialscloud.org:ybgqt-ewh55 mcid:2026.18 eng Materials Cloud https://archive.materialscloud.org/communities/mcarchive https://doi.org/10.24435/materialscloud:f2-nn info:eu-repo/semantics/openAccess Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode rarefied gas air drag accommodation coefficients molecular dynamics alumina graphene graphite coating defects Defects, corrugation and temperature govern rarefied-air drag on graphene coatings info:eu-repo/semantics/other