Aerodynamic and aeroacoustic properties of a forced rotating circular cylinder

This study employs a three-dimensional wall-resolved large eddy simulation in conjunction with the Ffowcs Williams–Hawkings acoustic analogy to systematically investigate the evolution of aerodynamic and aeroacoustic characteristics of a forced rotating cylinder over a Reynolds number range of 0.5×104 to 6×104 and a rotation ratio range of α=0–2. The results indicate that forced rotation can significantly reduce aerodynamic drag by delaying flow separation, with a maximum drag reduction of 82% (Re = 6×104, α=2). Simultaneously, it enhances lift by amplifying the negative pressure peak on the upper surface of the cylinder, leading to a maximum increase in lift-to-drag ratio by up to 18 (Re = 2×104, α=2). Moreover, forced rotation effectively suppresses both tonal noise from vortex shedding and broadband noise from turbulence, achieving a maximum reduction in overall sound pressure level (OASPL) of about 20 dB in the far field (Re = 6×104, α=2). Normalized noise analysis reveals that the far-field noise peak and OASPL can be predicted by 0.4α and 0.1α scaling laws, respectively, when the Reynolds number exceeds 0.5×104. Further analysis shows that Reynolds number effects are more pronounced at low rotation ratios (α ⩽ 1) and diminish under high rotation ratios (α⩾1). Additionally, forced rotation demonstrates superior control performance in flow reconstruction and noise suppression at higher Reynolds numbers. Evaluation of control efficiency confirms the engineering feasibility and potential of the forced rotation technique across a broad range of operating conditions.