Computational Investigation of Flow Over Two Side-by-Side Rotating Cylinders

This study uses numerical simulations to investigate the complex fluid dynamics around two adjacent rotating cylinders arranged side by side. The primary focus is on understanding the influence of Reynolds number (Re), rotational speed ([Formula: see text]), gap spacing ([Formula: see text]), and compressibility effects at different Mach numbers ([Formula: see text]). Simulations were performed using ANSYS Fluent 19.0, employing a finite volume-based solver and the shear stress transport (SST) [Formula: see text]–[Formula: see text] turbulence model. The numerical methodology is validated against experimental results for flow over a single rotating cylinder and numerical studies for the two-cylinder configuration. The analysis encompasses velocity magnitude contours, pressure distributions, vorticity patterns, and drag coefficients to elucidate the intricate flow interactions over two vertically placed side-by-side cylinders. Across Reynolds numbers ranging from 50 to 200, the flow exhibits distinct transitions from laminar to turbulent regimes, characterized by forming vortices and emerging flow separation zones. Higher Reynolds numbers generally lead to more turbulent and asymmetric flow patterns, increasing drag coefficients due to intensified wake formation and vortex shedding. The cylinders’ rotational speed significantly influences flow dynamics: lower speeds favor symmetric vortex formations, while higher speeds induce complex turbulent flows with enhanced vortex shedding. Outward rotation of the cylinders accelerates flow between them, increasing velocities and drag coefficients, whereas inward rotation reduces velocities and drag coefficients due to reduced flow interactions. Alterations in the gap spacing ([Formula: see text]) between cylinders reveal critical insights: smaller gaps intensify rotational effects, enhancing vortex shedding and increasing drag coefficients, whereas larger gaps promote stable flows with reduced vortex-shedding tendencies and lower drag coefficients. Compressibility effects at Mach numbers ranging from 0.2 to 0.8 amplify wake elongation, flow compression, and asymmetric vortex shedding, contributing to higher drag coefficients in transonic and supersonic regimes. This study advances understanding of fluid dynamics around cylindrical configurations, providing insights essential for optimizing engineering designs and performance across various applications. Future research directions may involve refining models, exploring additional parameters, and advancing predictive capabilities further to enhance practical insights into similar fluid flow phenomena.