THE EFFECT OF ROTATION AND PULSATING THROUGHFLOW ON THE ONSET OF LONGITUDINAL CONVECTIVE ROLLS IN A POROUS MEDIUM SATURATED BY NANOFLUID

This study accentuates the combined effect of rotation and pulsating throughflow on the onset of longitudinal convective rolls in a porous medium saturated by nanofluid. Pulsating throughflow modifies the basic profiles for temperature and the volumetric fraction of nanoparticle from linear to nonlinear with layer height, which in turn affects the stability significantly. To treat this problem, Buongiorno's two-phase mathematical model is used. Using the framework of linear stability theory and the frozen profile approach, the stability equations are derived and solved analytically using the Galerkin weighted residuals method. The effect of increasing the modified diffusive ratio NA and the nanoparticle Rayleigh-Darcy number RN, and decreasing the rotation parameter TD is to accelerate the onset of convection, while the Lewis number Le and porosity parameter f have dual effect on the stability of the system in the presence of pulsating throughflow. Moreover, the frozen profile approach shows that the effect of pulsating throughflow in both directions is stabilizing. An increased amplitude of throughflow oscillations leads to increased stability by an amount that depends on frequency.