Investigation of the drag coefficient of rotational fluid damper using computational fluid dynamics

Abstract

Dampers are essential devices used to absorb or dissipate vibration energy, contributing significantly to structural vibration control. An innovative rotational fluid damper (RFD) utilizing water as can energy dissipation medium has been developed. This damper generates substantial resistance to relative motion between its terminals when submerged in water, offering a significant damping effect to effectively mitigate excessive vibrations of structures. In this study, computational fluid dynamics (CFD) simulations are employed to thoroughly investigate the mechanical behaviors of the RFD. The configuration and mechanical model of the RFD are first introduced. Subsequently, the CFD model of the RFD is developed in ANSYS/Fluent and validated through comparison with experimental test data. Based on the validated model, the influences of six critical parameters on the drag coefficient of the RFD are comprehensively analyzed, including the Keulegan-Carpenter ($KC$) number, oscillation frequency, length-to-radius ratio, thickness-to-radius ratio, number and perforation ratio of the turning plates. The results indicate that when $KC$ > 0.4, the drag coefficient of the RFD is almost independent of the $KC$ number, oscillation frequency, length-to-radius ratio, and thickness-to-radius ratio, while it is negatively correlated with the number and perforation ratio of the turning plates. In addition, the drag coefficient of the RFD is significantly influenced by the $KC$ number when $KC$ < 0.4. This study provides an in-depth understanding of the RFD and paves the way for potential engineering applications.