Study of Kpers?Lortz Instability in a Weakly Electrically Conducting Couple-Stress Fluid

Title

Study of Kpers?Lortz Instability in a Weakly Electrically Conducting Couple-Stress Fluid

Creator

Reddy, B. Sirisha; Pranesh, S.; Siddheshwar, P.G.

Description

The study aims to investigate the Kpers?Lortz instability in rotating RayleighBard convection of a weakly electrically conducting couple-stress fluid. A novel aspect of this study is the incorporation of weakly electrically conducting couple-stress fluid in a rotating RayleighBard setup to analyze Kpers?Lortz instability and examine heat transfer in both primary and secondary regimes. The main goal is to understand how the combined effects of the couple-stress, rotation, and magnetic field alter stability thresholds and impact the heat transfer. KpersLortz instability (KLI) means the roll systems obtained during the regular convection get deformed and form an angle with each other, making the system unstable. The critical Rayleigh number for regular convection is obtained using linear stability analysis. A ninth-order Lorenz model is obtained using truncated Fourier expansions to study secondary instability. A weak magnetic field (Hartmann number) and couple-stress parameter hinders the onset-of-regular convection. We also obtain the critical values at which the KLI manifests. The critical values are found at a marginal steady state. The Hartmann number and couple-stress parameters hinder the onset-of-secondary instability. Further, the Nusselt number expression is derived, and it is observed that an increase in the couple-stress parameter and Hartmann number diminishes the heat transfer. Additionally, the Nusselt number is obtained for primary and secondary regimes, showing the impact of the parameters on the efficiency of heat transfer in each regime. To validate the results on secondary instability, the study compares its findings with existing literature in the absence of a weak magnetic field and couple-stress effects. A reasonably good agreement is observed, confirming the reliability of the results. 2025 Wiley Periodicals LLC.

Source

Heat Transfer;Volume;54;Issue;6;pp.3947-3959

Date

01-01-2025

Publisher

John Wiley and Sons Inc

Subject

couple-stress fluid; Hartmann number; heat transfer; KpersLortz instability; magnetic field

Coverage

Reddy B.S., Centre for Mathematical Needs, Department of Mathematics, Christ University, Karnataka, Bengaluru, India; Pranesh S., Centre for Mathematical Needs, Department of Mathematics, Christ University, Karnataka, Bengaluru, India; Siddheshwar P.G., Centre for Mathematical Needs, Department of Mathematics, Christ University, Karnataka, Bengaluru, India

Rights

Restricted Access; Hardcopy may be available in the library

Relation

ISSN: 26884534;

Format

online

Language

English

Type

Article

Identifier

https://doi.org/10.1002/htj.23392

https://www.scopus.com/pages/publications/105007037487?origin=resultslist