https://doi.org/10.1140/epjp/s13360-023-03903-8
Regular Article
Effect of small-amplitude gravity modulation on the stability of Rayleigh–Bénard convection in nanofluids
Department of Mathematics, Malaviya National Institute of Technology, 302017, Jaipur, Rajasthan, India
a ompsuthar@gmail.com, ompsuthar.maths@mnit.ac.in
Received:
17
September
2022
Accepted:
12
March
2023
Published online:
30
March
2023
Predicting the criteria for a convective flow to set up in a bottom heated fluid layer, due to density variations and the action of gravity, is essential in several physical phenomena, such as the cooling of electronic equipment and nuclear reactor design. The present article investigates the onset of convection in a nanofluid layer heated from below when the layer is subjected to a periodically modulated gravitational field of small amplitude. We assume that the layer is top-heavy, so the preferred convection mode is stationary. Our focus is on the shift in the critical Rayleigh number for constant gravitational field conditions, which is assumed to be of order square of the modulation amplitude. This shift in the Rayleigh number is obtained through a linear stability analysis of the governing system of equations. The stability criteria are obtained for three different sets of velocity boundary conditions. The effect of various parameters on the system’s stability under the modulated gravitational field is reported. The results reveal that gravity modulation significantly influences the onset of convection as through proper tuning of modulation frequency, one can further destabilize or even stabilize an unstable basic state resulting from the bottom-heating of the top-heavy layer. A comment on the inclusion of the Brownian motion effect in natural convection problems is made based on current findings and some existing studies indicating the same.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
