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Lookup NU author(s): Dr Francesco Zonta
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2023, The Author(s). We investigate the dynamics of turbulence and interfacial waves in an oil–water channel flow. We consider a stratified configuration, in which a thin layer of oil flows on top of a thick layer of water. The oil–water interface that separates the two layers mutually interacts with the surrounding flow field, and is characterized by the formation and propagation of interfacial waves. We perform direct numerical simulation of the Navier-Stokes equations coupled with a phase field method to describe the interface dynamics. For a given shear Reynolds number, Reτ= 300 , and Weber number, We= 0.5 , we consider three different types of oils, characterized by different viscosities, and thus different oil-to-water viscosity ratios μr= μo/ μw (being μo and μw oil and water viscosities). Starting from a matched viscosity case, μr= 1 , we increase the oil-to-water viscosity ratio up to μr= 100 . By increasing μr , we observe significant changes both in turbulence and in the dynamics of the oil–water interface. In particular, the large viscosity of oil controls the flow regime in the thin oil layer, as well as the turbulence activity in the thick water layer, with direct consequences on the overall channel flow rate, which decreases when the oil viscosity is increased. Correspondingly, we observe remarkable changes in the dynamics of waves that propagate at the oil–water interface. In particular, increasing the viscosity ratio from μr= 1 to μr= 100 , waves change from a two-dimensional, nearly-isotropic pattern, to an almost monochromatic one.
Author(s): Giamagas G, Zonta F, Roccon A, Soldati A
Publication type: Article
Publication status: Published
Journal: Flow, Turbulence and Combustion
Year: 2024
Volume: 112
Issue: 1
Pages: 15-31
Print publication date: 01/01/2024
Online publication date: 12/09/2023
Acceptance date: 15/08/2023
Date deposited: 07/02/2025
ISSN (print): 1386-6184
ISSN (electronic): 1573-1987
Publisher: Springer Nature
URL: https://doi.org/10.1007/s10494-023-00478-3
DOI: 10.1007/s10494-023-00478-3
Data Access Statement: The authors provide in the manuscript all data necessary to understand, evaluate, replicate, and build upon the reported research. Possible complementary data can be found in the references cited by the authors.
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