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dc.contributor.authorNarayanan, Kiran
dc.contributor.authorSamtaney, Ravi
dc.date.accessioned2019-11-25T07:06:50Z
dc.date.available2019-11-25T07:06:50Z
dc.date.issued2019-11-06
dc.identifier.citationNarayanan, K., & Samtaney, R. (2019). On the role of thermal fluctuations in Rayleigh–Taylor mixing. Physica D: Nonlinear Phenomena, 132241. doi:10.1016/j.physd.2019.132241
dc.identifier.doi10.1016/j.physd.2019.132241
dc.identifier.urihttp://hdl.handle.net/10754/660218
dc.description.abstractWe study the significance of thermal fluctuations in fluid mixing that is induced by the Rayleigh–Taylor instability (RTI) using numerical solutions of the fluctuating compressible Navier–Stokes equations. Our results indicate that thermal fluctuations can trigger the onset of RTI at an initially unperturbed fluid–fluid interface and lead to mixing of multi-mode character with growth rates of αs = 0.035 and αb = 0.023 for the spikes and bubbles, respectively. In addition, we find that whether or not thermal fluctuations quantitatively affect the mixing behavior, depends on the magnitude of the dimensionless Boltzmann number of the system, and not solely on its size. When the Boltzmann number is much smaller than unity, the quantitative effect of thermal fluctuations on the mixing behavior is negligible and the behavior is the average of the outcome from several stochastic instances, with the ensemble of stochastic instances providing bounds on behavior. When the Boltzmann number is of order unity, we find that thermal fluctuations can significantly affect the mixing behavior; the ensemble-averaged solution shows a departure from the deterministic solution at late times. We conclude that for such systems, it is important to account for thermal fluctuations in order to correctly capture their physical behavior.
dc.description.sponsorshipAll simulations were performed on the CRAY XC-40 Shaheen-II at the KAUST Supercomputing Core Laboratory. This work was supported by the KAUST baseline research funds BAS/1/1349-01-01.
dc.publisherElsevier BV
dc.relation.urlhttps://linkinghub.elsevier.com/retrieve/pii/S0167278919303264
dc.rightsNOTICE: this is the author’s version of a work that was accepted for publication in Physica D: Nonlinear Phenomena. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Physica D: Nonlinear Phenomena, [[Volume], [Issue], (2019-11-06)] DOI: 10.1016/j.physd.2019.132241 . © 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
dc.titleOn the role of thermal fluctuations in Rayleigh–Taylor mixing
dc.typeArticle
dc.contributor.departmentFluid and Plasma Simulation Group (FPS)
dc.contributor.departmentInvestment Fund
dc.contributor.departmentMechanical Engineering Program
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalPhysica D: Nonlinear Phenomena
dc.rights.embargodate2021-11-06
dc.eprint.versionPost-print
kaust.personNarayanan, Kiran
kaust.personSamtaney, Ravi
kaust.grant.numberBAS/1/1349-01-01
kaust.acknowledged.supportUnitKAUST baseline research
kaust.acknowledged.supportUnitShaheen-II
kaust.acknowledged.supportUnitSupercomputing Core Laboratory
dc.date.published-online2019-11-06
dc.date.published-print2020-01


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