Entropy generation in peristaltic transport of Al2O3 and γ-Al2O3 nanoparticles between two sinusoidally deforming curved tubes

This work examines the peristaltic motion of Al 2 O 3 and γ-Al 2 O 3 nanofluids in curved concentric tubes with sinusoidal wall deformation. The study is important because such flows occur in medical procedures like endoscopy and catheterization, and in industrial systems with narrow curved channels. The mathematical model includes viscous dissipation in the heat transfer equation to study entropy generation. By applying the lubrication approximation under long-wavelength and low-Reynolds-number assumptions, exact analytical solutions are obtained for velocity, pressure gradient, temperature, and entropy production. The results show that velocity increases with higher flow rate and curvature, while the pressure gradient rises with larger amplitude and curvature but decreases with flow rate. The temperature profile grows with both flow rate and Brinkman number. Entropy generation increases with temperature difference but decreases when viscous dissipation is stronger. Streamline analysis shows that curvature enhances trapping near the endoscopic wall, while a higher flow rate reduces trapped boluses. The novelty of this study lies in modeling a flexible peristaltic endoscope inside a curved sinusoidal tube, which better represents the natural shape of biological organs compared to earlier straight or rigid models. The findings provide useful insight for improving nanofluid transport in both medical and engineering applications.