Numerical Investigation of Vortexinduced Vibrations (Viv) of A Rotating Cylinder in In-Line and Cross-Flow Directions Subjected to Oscillatory Flow

Abstract

This study aims to explore the phenomenon of Vortex-Induced Vibration (VIV) generated by cylinder undergoing rotation at different rotation rates (α = 0, 0.25, 0.5, 0.75, and 1) while being subjected to oscillatory flow in two dimensional numerical simulations. The simulations use two different Keulegan-Carpenter (KC) numbers KC = 5 and 10, at Reynolds number Re = 150. A widespread reduced velocities range. This research purpose is to explore the phenomenon of Vortex-Induced Vibration (VIV) generated by a cylinder undergoing rotation at different rotation rates ( α = 0, 0.25, 0.5, 0.75, and 1) while being subjected to oscillatory flow. The results demonstrate that vibration amplitude in inline and cross-flow directions is significantly influenced by the rotation provided to cylinder, as well as the KC number and Vr. However, it is observed that the cross-flow direction vibrations are more profoundly affected by the rotation. Case of the stationary cylinder (α = 0), the VIV amplitude in cross-flow direction almost diminishes once the critical value of reduced velocity is surpassed, specifically Vr = 6 for KC = 5 and Vr = 11 for KC = 10. On other hand, for rotating cylinders (α ≠ 0), the vibration amplitude reaches zero only at the critical value of reduced velocity. Beyond this point, it gradually increases and eventually stabilizes. The critical reduced velocity, which determines the point at which the vibration amplitude essentially becomes zero, depends on the cylinder's relative motion and is considered the critical reduced velocity when the effective KC number (KCeff) is very small and same trent also observed for effective reduced velocity (Vr eff) are small. It should be noted that at significantly higher reduced velocities, a non-vortex shedding regime occurs, indicating a distinct flow behavior