Darcy–Forchheimer up/downflow of entropy optimized radiative nanofluids with second-order slip, nonuniform source/sink, and shape effects

This article examines the influence of single-walled carbon nanotube (SWCNT)/multi-walled carbon nanotube (MWCNT) nanoparticles shapes on the radiative up and down flow of nanofluids past a thin needle. This nanofluid flow is considered in the presence of Darcy-Forchheimer effects, thermal radiation, Wu's slip, and non-uniform heat source/sink. Brick, cylinder, platelet, and blade shapes of nanoparticles are considered. Numerical solutions are attained by a well-known shooting technique. A comprehensive discussion regarding the effects of physical parameters on velocity, temperature, skin friction coefficient, and local Nusselt number is carried out. Outcomes reveal that fluid velocities of SWCNT/MWCNT-Water nanofluids behave in the opposite manner in up and down flows of nanofluids in the order of brick, cylinder, platelet and blade-shaped nanoparticles. The porosity parameter regulates the heat transfer rate efficaciously. The surface viscous drag intensifies for the nanofluids involving the nanoparticles in the order of their shapes as brick, blade, cylinder, and platelet.