Linear and Weakly Nonlinear Study of Magnetoconvection in a Couple‐Stress Fluid in the Presence of Suction–Injection–Combination

ABSTRACT The linear and weakly nonlinear study addresses the impact of a suction–injection–combination (SIC) on magnetoconvection in a couple‐stress fluid. Linear stability analysis uses the normal‐mode technique to obtain the critical Rayleigh number expression. The autonomous fifth‐order Lorenz model is derived for weakly nonlinear analysis using the minimal representation of truncated Fourier series. The heat transport rate is discussed by arriving at a Nusselt number expression by solving the fifth‐order autonomous Lorenz model. This study reveals that the couple stress enhances the system's stability and transport of heat under the combined influence of the magnetic field and the SIC. The study concludes that the stability of the system and heat transfer can be controlled by fine‐tuning the Peclet number.