Numerical Simulation of Flow and Heat Transfer Around Diamond‐Shaped Porous Cylinders With Variable Apex Angles at Low Reynolds Numbers

ABSTRACT Porous‐fluid systems, which consist of a porous medium structure and a flow passing over it, play a crucial role in aerospace engineering and heat exchanger design. This study aims to investigate the influence of geometric parameters and porous medium properties on flow and heat transfer characteristics around a porous diamond‐shaped cylinder. A cylinder with variable apex angles (30° ≤ θ ≤ 150°) is numerically analyzed in a two‐dimensional channel using the finite element method (FEM). The effect of Darcy number (10 −5 ≤ Da ≤ 10 −2 ), Reynolds number (10 ≤ Re ≤ 40), and the presence of heat source in the porous region are systematically analyzed. Flow visualization based on the Q criterion highlights regions where vorticity dominates over the strain rate, providing insight into vortex formation mechanisms. Results show that under specific conditions, increasing the apex angle ( θ ) from 30° to 150° leads to a 166% increase in the drag coefficient ( C d ), highlighting the significant impact of geometry on flow resistance. For the cases with an internal heat source, the mean Nusselt number ( Nu ) increases with decreasing Darcy number ( Da ), suggesting improved heat transfer performance. Specifically, at Re = 40, reducing Da from 10 −2 to 10 −5 results in an 18.5% to 28.8% enhancement to Nu . Furthermore, this study proposes a new correlation for the drag coefficient ( C d ) and Nusselt number ( Nu ) derived from the present simulation results. This correlation is established based on the Reynolds number ( Re ), Darcy number ( Da ), and apex angle ( θ ). The purpose is offering insights into optimizing porous media configurations in aerospace aerodynamics and microchannel heat exchanger designs.