Upamali, W.G.D.H.Karunarathna, W.H.D.T.Dewasurendra, M.T.M.2025-11-172025-11-172025-07-07Proceedings International Conference on mathematics and Mathematics Education(ICMME) -2025, University of Peradeniya, P 25978-624-5709-03-8https://ir.lib.pdn.ac.lk/handle/20.500.14444/6675The study of non-Newtonian fluid dynamics has attracted considerable interest due to its diverse applications in both industrial and biomedical fields. Among various non-Newtonian fluids, Ellis fluid is particularly noteworthy for its shear-thinning behaviour. In this context, researchers have examined the flow and heat transfer characteristics of an Ellis hybrid nanofluid over a stretching cylinder, incorporating the effects of magnetic fields, Darcy– Forchheimer drag, nonlinear thermal radiation, and Joule heating. This study further investigates these phenomena by accounting for the influence of buoyancy forces. The hybrid nanofluid comprising a non-Newtonian Ellis base fluid embedded with AA7072 and AA7075 nanoparticles suspended in water, offers enhanced thermal and rheological properties. To analyze the system, the governing equations for continuity, momentum, and energy are reduced to a set of nonlinear ordinary differential equations through similarity transformations. These equations are then solved using the Optimal Homotopy Analysis Method (OHAM), a semi- analytical technique that allows flexibility in selecting auxiliary linear operators and initial guesses. Graphical results, generated via the Mathematica software, illustrate the variations in fluid velocity and temperature profiles in response to different physical parameters. To validate the accuracy of the OHAM solutions, error comparisons are made against results obtained from the finite difference method. The analysis confirms that OHAM is a robust and effective approach for investigating complex fluid flow and heat transfer phenomena in non-Newtonian hybrid nanofluids.en-USBuoyancy forceEllis hybrid nanofluidJoule heatingOptimal homotopy analysis methodArticle