Biological transmission in a magnetized reactive Casson–Maxwell nanofluid over a tilted stretchy cylinder in an entropy framework

Abstract

Biological transmission (or bioconvection) offers a huge room for studying the interplay between microorganisms and fluid dynamics. The understanding of bioconvection is relevant for studying microbial ecology, population dynamics and exploring the behaviour of microorganisms in complex environments. The objective of this research work is to delve into the physical and biochemical aspects of bioconvection in a magnetized Casson–Maxwell nanofluid containing gyrotactic microorganisms. The investigation is conducted on a tilted elongated cylindrical surface, taking into account the presence of entropy generation. Arrhenius activation energy and slip and convective boundary conditions are novel aspects of this research. The current model invokes the impacts of thermophoresis diffusion, and Brownian motion impacts using the Buongiorno model. The Casson–Maxwell fluid model is employed to expound the rheological behaviour of non-Newtonian nanofluids with the migration of gyrotactic microorganisms. The similarity functions are used to convert the model equations and the related boundary conditions into dimensionless form. The insightful numerical results are developed by implementing the ND Solver in Mathematica, providing valuable insights into the velocity, thermal, concentration, and microorganism fields, as well as the rate of entropy generation and other engineering quantities. Outcomes are presented as graphs and tables for further analysis and discussion. The computational findings unravel several significant contributions of influential model parameters. The Lorentz force and porosity are found to create a drag force that deters the fluid pace, while the reverse trend holds for the fluid temperature. Higher activation energy results in a growth in the concentration field. A larger Peclet number leads to a decline in microorganism density. Furthermore, motile microorganisms’ density and swimming speed significantly influence entropy inflation. A 10% increase in magnetic strength results in a 1.47% increase in skin friction for the Casson fluid model and a 1.32% increase in skin friction for the Casson–Maxwell fluid model. This study contributes to understanding bioconvection in reactive Casson–Maxwell nanofluids with gyrotactic microorganisms and sheds light on entropy production in biological systems.