Radiation-Driven Flow and Heat Transfer of Couple Stress Hybrid Nanofluids over a Shrinking Riga Plate

Abstract

This study examines the flow and heat transfer characteristics of a couple-stress hybrid nanofluid over a permeable shrinking Riga plate comprising aluminium alloys (AA7072 and AA7075) with methanol (CH₃OH) as the base fluid. The flow is influenced by the presence of an electrically actuated Riga plate, which generates a Lorentz force, promoting boundary layer stabilisation. The couple stress fluid model accounts for microstructural effects, adding complexity to the momentum equations. Similarity transformations are employed to simplify the governing partial differential equations into ordinary differential equations, which are then solved numerically using the MATLAB bvp4c solver. The effects of the considered parameters are analysed in detail. The results demonstrate that the existence of the hybrid nanoparticles and the couple stress parameter considerably influence the flow behaviour and heat transfer performance. These findings provide new insight for the control of boundary layer flow in micro- and nanoscale cooling systems.