NONLINEAR DOUBLE-DIFFUSIVE CONVECTION IN AN ANISOTROPIC POROUS LAYER UNDER TIME-DEPENDENT ROTATION WITH INTERNAL HEATING AND SORET EFFECT

The study investigates the double-diffusive convection onset in a non-uniformly rotating anisotropic porous fluid layer under the influence of Soret and internal heating effects. The linear stability approach is employed to investigate the system when subjected to infinitesimal perturbations. The nonlinear case is investigated using a minimum truncated double Fourier series, leading to the derivation of nonlinear Lorenz-type equations. To solve these coupled equations, a local quasilinearization block hybrid method (LQBHM) is utilized. The analysis shows that the stability of the fluid system is dependent on the values of the Soret coefficient, rotation parameter, anisotropy parameters, and internal heating. Among other results, it was observed that the rotation and thermal anisotropy parameters have stabilizing effects on the fluid system. Additionally, the rotation modulation amplitude increases the rates of heat and mass transfer and so advances the onset of convection in the fluid system, whereas the modulation frequency has the opposite effect.