Impact of groove on flow patterns and heat transfer over circular cylinders: A power-law fluid perspective

Understanding the flow behavior of non-Newtonian fluids around circular cylinders is critical for optimizing aerodynamic performance and enhancing heat transfer in various engineering applications, including chemical processing, biotechnology, and polymer extrusion. This study numerically investigates the impact of a square groove on the upper surface of a circular cylinder immersed in power-law fluids. The flow is considered laminar, steady, and incompressible, with a Prandtl number of 0.7 and Reynolds numbers (Re) ranging from 10 to 40. The study specifically focuses on non-Newtonian fluids characterized by power-law indices (n) ranging from 0.2 to 1. The discretization of the governing Navier–Stokes and energy equations is achieved via the finite volume approach. Our findings reveal that the grooved cylinder consistently exhibits a higher pressure coefficient (Cp) and significantly delays flow separation compared to a smooth cylinder. As Re increases, the drag coefficient (CD) decreases for all values of n. Heat transfer characteristics are notably influenced by the interplay between Re and n, with Re0.40931 and n−0.13330. The grooved configuration enhances the average Nusselt number by 16.78%–29.75% over a smooth cylinder. Additionally, a predictive model is established for the CD and Nu as functions of Re and n, providing a reliable framework for flow and heat transfer predictions in power-law fluids. This study provides novel insights into the interaction of flow separation, vortex dynamics, and thermal transport in non-Newtonian fluid flows over grooved cylinders, offering valuable design implications for energy-efficient thermal and fluid transport systems.