Abstract This study presents a numerical analysis of flow and heat transfer performance around five bluff bodies considered as vortex generators, which are designed with an identical hydraulic diameter ( D h ). The bluff bodies are circular, bullet-shaped, square, equilateral triangle, and hexagonal cylinders, with smooth and sharp edges. When Re = 200, the bluff bodies are immersed individually in a narrowed channel with a variable gap ratio between the channel wall and the cylinder surfaces (0.5 ≥ GR = y/D h ≥ 2.0). The problem is crucial since the results are beneficial to designing and optimizing heat transfer equipment. The bottom wall was maintained at a higher temperature than the inlet flow to investigate thermal flow characteristics due to presence of vortex generators. The analysis revealed a critical transition in flow behavior between GR = 0.75 and GR = 1.0. It is found that bottom wall heat transfer diminishes after GR ≥ 1 as wider spacing reduces confinement and promotes slower thermal dissipation. It is observed that despite the hexagon’s sharp chamfered edge, its performance was comparable to that of the circular body. The smaller triangular prism scaled by circular diameter, exhibited comparable trends with the larger prism. However, nearly 20% performance discrepancy was observed due to dimensional variations.
Sambu et al. (Fri,) studied this question.