Impact of activation energy and thermal radiation on hybrid nanofluid (engine oil + nickel zinc ferrite + manganese zinc ferrite) flow over a wavy cylinder in the presence of induced magnetic field

Wavy cylinders add more complexity to the flow than smooth cylinders. Analyzing this flow helps researchers understand phenomena like boundary layer behavior, drag forces, and heat transfer patterns in real-world scenarios with uneven surfaces. For instance, this knowledge can be applied to understanding flow around underwater structures like pipelines or ship hulls. This study investigates the novel influence of activation energy on radiative hybrid nanofluid flow past a wavy cylinder subjected to an induced magnetic field. We use engine oil containing a mixture of nickel zinc ferrite and manganese zinc ferrite nanoparticles as the base fluid, providing a unique combination of materials not previously explored in this context. We have transformed the problem's equations into a collection of ordinary differential equations and skillfully resolved them using the bvp4c solver. Using bar graphs, the relevant physical characteristics, including the Nusselt number, are discussed. The outcomes for the saddle stagnation-point and nodal stagnation-point scenarios are displayed. Results show that friction factor rises with increasing volume fraction of nickel zinc ferrite and declines with increasing magnetic parameter; these are the main conclusions drawn from the study. The friction factor shrinks at a rate of 0.6803 for nodal stagnation points and 0.73692 for saddle stagnation points when the magnetic parameter is between 0.05 and 0.3. The Sherwood number lowers by 0.0046 (in the case of a nodal stagnation point) and 0.00512 (in the case of a saddle stagnation point) when the activation energy parameter is between 0 and 2. It is also found that as thermal radiation increases, the fluid temperature rises. The findings have implications for designing microfluidic devices, optimizing heat exchanger performance in the presence of magnetic fields, and managing thermal dissipation in miniaturized electronics using wavy surfaces and controlled thermal radiation.