Hydrodynamic and thermal analysis of Newtonian fluid flow in a corrugated backward facing step channel under forced convection

This study numerically investigates the thermo-hydraulic characteristics of forced convection flow of Newtonian fluids in a corrugated backward-facing-step (BFS) channel using the Galerkin finite element method. The effects of Reynolds number Re (= 5–200), Prandtl number Pr (= 0.72–100), non-dimensional corrugation amplitude α (= 0.3–0.7), and wavelength λ (= 0.5–1.5) on flow and heat transfer are systematically analyzed. The results show that increasing Pr reduces the thermal boundary-layer thickness at trough zone diminishes gradually for lower Re value, while at higher Re (=200), resulting in a higher rate of reduction. The corrugated geometry promotes flow separation, recirculation, and thermal boundary-layer disruption, thereby improving convective heat transfer compared with a plain BFS channel. The enhancement ratio ( ER ) exhibits non-monotonic behavior with Pr at lower Re , whereas a monotonic variation is observed at higher Re (=200). The performance factor ( PF ) is employed to evaluate the combined effects of heat transfer enhancement and pressure drop. The PF exhibits non-monotonic variations with Pr at lower Re , whereas a monotonic trend is observed at higher Re . Furthermore, the PF exhibits a non-monotonic variation with Re at higher Pr and smaller λ , whereas at higher λ , it decreases monotonically with increasing Re across all Pr values . At Re = 100 and Pr = 100, the PF decreases from approximately 0.61 to 0.56 as λ increases from 0.5 to 1.5 at α = 0.3, while a minimum value of about 0.16 is obtained at α = 0.7 and λ = 1–1.5. The findings provide useful insights into enhanced heat transfer in corrugated BFS channels, offering guidance for the design of compact heat exchangers and other thermal management systems.