Session: 08-06-01 non-presentations

Paper Number: 124234

124234 - Experimental Investigation of Low Mass Ratio Pivoted Cylinders Undergoing Vortex-Induced Vibrations 

This study presents an experimental investigation of low mass ratio pivoted cylinders undergoing vortex-induced vibrations (VIV) under different boundary and water surface conditions. Three distinct cylinders, each possessing a unique mass ratio, were examined under two pivotal configurations: one from the top of the water tank and the other from the tank's bottom. The study aimed to analyze the influence of bottom boundary conditions and water surface conditions on the VIV response of these cylinders.

Our findings reveal that asymmetric loading on the cylinder, such as partial submersion, results in lower amplitude responses compared to fully submerged cylinders. Moreover, added mass in low mass ratio systems demonstrates a profound impact on cylinder motion. For example, the spanwise amplitude response demonstrates nonlinearity, which is frequently observed through the manifestation of tear-drop, figure eight, or circular patterns. Occasionally, these patterns are observed to exhibit a frequency ratio of 1-1 between in-line and cross-flow motions, although multiple frequencies are more commonly observed.

Observations regarding added mass distribution and energy transfer along the cylinder's span align with the observed complex motions. This research provides valuable insights into the effects of boundary and surface conditions on VIV, which are crucial for various engineering applications in marine and offshore structures.

Presenting Author: Ersegun Deniz Gedikli University of Hawaii at Manoa

Presenting Author Biography: Deniz Gedikli is an Assistant Professor at the University of Hawaii at Manoa's Department of Ocean and Resources Engineering. Prior to joining UH-Manoa, he was a postdoctoral fellow at the Norwegian University of Science and Technology (NTNU), where he worked on various offshore renewable energy and Arctic engineering projects. He earned his PhD from the University of Rhode Island's Department of Ocean Engineering in 2017. His research interests include fluid-structure interactions, nonlinear dynamics, data science, flow-induced vibrations, Arctic offshore structures and marine operations, and offshore renewable energy systems.

Authors:

Ersegun Deniz Gedikli University of Hawaii at Manoa
Clara Encke University of Hawaii at Manoa