Session: 08-01-01 Risers, Pipelines & VIV

Paper Number: 103724

103724 - Cfd Simulation of Vortex-Induced Vibration of a Flexible Cylinder With Buoyancy Module Under Uniform Flow Using a Two-Way Coupled Model 

The flexible cylinder attached to the buoyancy module alters the geometric shape of the flexible cylinder and influences the fluid forces, leading to a change in the response characteristics of the flexible cylinder. The buoyancy module coverage rate, staggered buoyancy module length, gap, and module aspect ratio are the influencing factors of the VIV response of the flexible cylinder. Limited research was carried out experimentally and numerically on the VIV response characterization of the flexible cylinder with the buoyancy module. The present two-way coupled fluid-structure interaction model focused on how the buoyancy module coverage rate influences the VIV response of flexible cylinders at fixed L/D=100, m*=2.55, and EI=2.95 at various V_r subjected to uniform current. The force coefficients and the structural responses in the time domains are converted into frequency domain responses using Fast Fourier Transform (FFT). The cylinder with the buoyancy module exhibits two frequency responses: lower and higher frequency components. The lower frequency corresponds to the buoyancy module, and the higher frequency is for the cylinder. The buoyancy module acts as a response controller in the crossflow direction, and the buoyancy module dominates the VIV response at a lower reduced velocity (V_r). The excitation of the lower frequency component is diminished as the Vr increases, and it shows that the bare cylinder dominates the cylinder VIV. However, the inline RMS response of the flexible with buoyancy module is higher than the bare cylinder.

Presenting Author: Karthikeyan S IIT, Madras

Presenting Author Biography: I am currently pursuing my Ph.D. at IIT Madras in the Department of Ocean Engineering under the guidance of Dr. S. Nallayarasu. My present research work is on the Vortex-induced vibration of the flexible cylinder

Authors:

Karthikeyan S IIT, Madras
Nallayarasu S IIT Madras