Internal heat source effects on thermosolutal convection of Casson nanofluids embedded by Darcy-Brinkman model

Abstract

The current study investigates Darcy-Brinkman convective instability for a non-Newtonian binary nanofluid layer in the presence of internal heat source. Non-Newtonian fluid behavior is characterized by Casson model. Normal mode technique is employed to convert the relevant PDEs into ODEs and Boussinesq approximation is used. The phenomenon is explored for both stationary as well as oscillatory modes of convection. The novelty and significance of the work lie in the fact that oscillatory motions have come into existence due to the presence of internal heat source term in the thermal energy equation which were non-existent otherwise for top-heavy configuration of nanoparticles. The impact of various nanofluid and solute parameters except solute Rayleigh number is found to destabilize the nanofluid layer while solute Rayleigh number, Darcy number and porosity parameters are found to postpone the onset of convection. Non-Newtonian Casson parameter and internal heat source strength are found to hasten the convection for the present arrangement of nanoparticles.