Exploration of the dynamics of heated non-Newtonian Casson fluid within an annular region of eccentric cylinders subject to peristaltic motion

The flow of non-Newtonian fluids is widely observed in industry and biology, for example, enhanced oil recovery, chemical processes such as in distillation towers and fixed-bed reactors and in the applications of pumping fluids such as synthetic lubricants, colloidal fluids, liquid crystals, and biofluids (e.g., animal and human blood). Therefore, the present study delineates the heat transfer analysis of a Casson fluid within the annular region of eccentric cylinders subjected to peristaltic motion, considering the influence of thermal radiation. The outer cylinder remains rigid and moves at a constant speed, while the inner cylinder, featuring a sinusoidal wave along its wall, exhibits flexibility. The governing two-dimensional equations for the movement of the Casson fluid are reformulated under the assumption of the lubrication hypothesis. The perturbation scheme is used to find approximate results for velocity, temperature, and pressure gradient. A graphical representation is utilized to study the fluctuation of various flow fields with different imperative parameters. The results reveal that the liquid velocity declines as the Casson parameter increases, while the temperature decreases due to the amplified effect of thermal radiation. This study has applications in endoscopy, which is important for diagnosing problems in internal organs. Additionally, the variation of the pressure gradient helps maintain the flow rate, which is essential during the insertion of a catheter into an artery.