Effects of mass ratio and rotation speed on flow induced vibration of a rotating cylinder with two degrees of freedom

Abstract

Rotating cylinders submerged in the fluid have many practical applications such as offshore wind turbines and drilling pipes. These rotating cylinders are usually subjected to vortex-induced vibrations, and heat transfer has a great effect on their efficiency. Therefore, it is very important to investigate the heat transfer from the rotating cylinder undergoing vortex-induced vibrations. The present study investigates the flow-induced vibration (FIV) of a rotating circular cylinder, along with the related convective heat transfer, for various mass ratios (mr), rotating rates (α), and a range of reduced velocity (3.0 ≤ ur ≤ 15). The cylinder is modeled as a two-degree-of-freedom system, whereby it is free to oscillate both in the streamwise and transverse directions. The results indicate that the rotational motion of the cylinder significantly enhances the cylinder's displacements in both directions. Furthermore, the displacement amplitude in both directions decreases with an increase in mr. For higher reduced velocities, the displacement amplitude becomes constant. Also, it is observed that increasing mr leads to an improvement in heat transfer for high reduced velocities. Also, the maximum value of the Nusselt number is 15.25 for the non-rotating cylinder and 14 for the rotating cylinder with α=1. The FIV of a rotating circular cylinder exhibits several vortex patterns, including 2S, 2P, P + S, and 2T.