ItemArticle

Study of internal heat source generated natural convection with sinusoidal and non-sinusoidal time-periodic vertical oscillations

Title
Study of internal heat source generated natural convection with sinusoidal and non-sinusoidal time-periodic vertical oscillations
Creator
Kruthik, P.S.; Idris, Ruwaidiah; Siddheshwar, P.G.
Description
This study explores the effect of gravity modulation on natural convection induced by a uniform internal heat source within a fluid-saturated porous medium, a topic of growing relevance in advanced thermal management applications. Four distinct gravity waveforms, square, sinusoidal, triangular, and sawtooth, are examined under three boundary condition combinations: Rigid-Adiabatic-Rigid-Isothermal (RARI), Rigid-Adiabatic-Free-Isothermal (RAFI), and Free-Adiabatic-Free-Isothermal (FAFI). A novel analytical framework is developed by integrating a Maclaurin series expansion with a minimal FourierGalerkin approach to derive a generalized Lorenz model. Linear stability analysis, via a modified Venezian method, to determine the critical internal Rayleigh number and its correction due to modulation. A weakly nonlinear analysis based on the GinzburgLandau equation also provides closed-form expressions for the mean Nusselt number, capturing heat transfer characteristics. The findings demonstrate that square wave modulation most effectively enhances heat transport, followed by sinusoidal, triangular, and sawtooth forms. The influence of key physical parameters reveals that increasing porous parameter (?2) and Brinkman number (?) suppress heat transfer, as do higher Prandtl numbers (Pr) and modulation frequencies (?). FAFI yields the highest heat transfer among the boundary types, while RARI performs the least. The novelty of this work lies in the combined analytical treatment of diverse waveform modulations while considering a uniform internal heat source and boundary condition for natural convection. 2025 The Author(s)
Source
Results in Engineering;Volume;27;Issue;;Article No.;106047;
Date
01-01-2025
Publisher
Elsevier B.V.
Subject
Brinkman-Bard convection; GinzburgLandau equation; Gravity modulation; Heat transport; Maclaurin series solution; Sawtooth; Sinusoidal; Square wave forms; Triangular
Coverage
Kruthik P.S., Special Interest Group for Modelling and Data Analytics (SIGMDA), Faculty of Computer Science and Mathematics, Universiti Malaysia Terengganu, Kuala Nerus, Terengganu, 21030, Malaysia; Idris R., Special Interest Group for Modelling and Data Analytics (SIGMDA), Faculty of Computer Science and Mathematics, Universiti Malaysia Terengganu, Kuala Nerus, Terengganu, 21030, Malaysia; Siddheshwar P.G., Centre for Mathematical Needs, Department of Mathematics, Christ University, Bengaluru, 560029, India
Rights
All Open Access; Gold Open Access; Green Open Access
Relation
ISSN: 25901230;
Format
online
Language
English
Type
Article

Citation

Kruthik, P.S.; Idris, Ruwaidiah; Siddheshwar, P.G., “Study of internal heat source generated natural convection with sinusoidal and non-sinusoidal time-periodic vertical oscillations,” CHRIST (Deemed To Be University) Institutional Repository, accessed June 18, 2026, https://archives.christuniversity.in/items/show/22441.

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