Groove-induced heat transfer enhancement and flow control around cylindrical surface

This research is motivated by the need to enhance the aerodynamic and thermal performance of bluff bodies by using passive control technique, which are widely employed in engineering systems, including heat exchangers, energy devices, and aerodynamic structures. The primary objective of this study is to numerically investigate the impact of a single trapezoidal groove on the heat transfer and flow behavior of a circular cylinder under steady, laminar, two-dimensional conditions for Reynolds numbers (Re) ranging from 10 to 40 and a Prandtl number (Pr) of 7. The groove is positioned at angular locations θ = 90°, 120°, and 150° from the front stagnation point. A key focus is the comparative performance between grooved and smooth cylinders (No groove) in terms of heat transfer enhancement and drag reduction. Computational fluid dynamics simulations based on the finite volume method are performed. The results indicate that the groove at θ = 90° provides superior performance, enhancing pressure recovery, delaying flow separation, and reducing wake length. This configuration achieves the greatest average Nusselt number (Nu¯) enhancement-ranging from 43.45% at Re = 10 to 37.59% at Re = 40 and yields highest drag CD reduction, with CD decreasing by 0.427%–0.613% as Re increases. Empirical correlations for Nu¯ and CD as functions of groove angle (in degrees) and Re are proposed. Nu¯ follows θ−0.342 and Re0.413, where as CD follows θ0.0110 and Re−0.4701. These findings confirm the θ = 90° groove as an effective passive control strategy in laminar flow regimes.