Surface Roughness Effect on Vortex-Induced Vibration Phenomenon in Cross-Flow Direction of a Bluff Body

Mohd Kushairi Mohd Ghazali; Nik Mohd Ridzuan Shaharuddin; Arifah Ali; Kang Hooi Siang; Mohd Nazri Mohd Nasir; Mat Hussin Ab. Talib

Authors

Mohd Kushairi Mohd Ghazali School of Mechanical Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor,Malaysia
Nik Mohd Ridzuan Shaharuddin School of Mechanical Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor,Malaysia
Arifah Ali
Kang Hooi Siang Marine Technology Center, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia
Mohd Nazri Mohd Nasir School of Mechanical Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor,Malaysia
Mat Hussin Ab. Talib School of Mechanical Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor,Malaysia

Keywords:

Marine growth, Roughness coefficient, Surface roughness, vortex induced vibration

Abstract

This paper presents the experimental result concerning the effect of surface roughness towards the vortex-induced vibration phenomenon on the offshore structure such as riser, which is represented by a bluff body. VIV can cause fatigue damage which is due to excessive vibration in the long run. Simultaneously, the unwanted aquatic organism will be developed at a certain depth of the underwater structure and the roughness of the structure will be changed dramatically. Therefore, it is crucial to investigate the effect of the surface roughness towards the VIV. In this study, A modelled cylinder pipe was mounted on a linear slider with two springs attached at both of its ends in a working section of a circulating water tank. Sandpaper with roughness coefficient varied from 0.19 × 10-3to 5.10 × 10-3was utilized to represent different surface roughness on the modelled body. The test covered the subcritical range of Reynolds number from 4.9 × 103to 1.5 × 104. The displacement of the body was measured at different reduced speeds. The results show that as the surface roughness of the body increases, the amplitude response decreases.