Wave action on oil rig cylinder members

• Main Author: Peh, Peng Boon.
• Other Authors: Adi Kurniawan
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Civil engineering::Water resources
• Online Access: http://hdl.handle.net/10356/16802
• Institution: Nanyang Technological University

During the last decade, the world demands more energy due to uprising giant countries like China and India. This resulted in an increase in the number of off-shore projects involving vertical column and a need to explore into the deeper seas to develop oil and gas fields. In fact, the wind energy which is an alternative source of green energy also faces similar engineering challenges in placing the foundations of offshore wind turbines. In actual situations, the wave run-up and wave impacts cause unexpected damage to boat landing facilities, platforms and underside of the deck. Recognizing this problem, a need for improvement in the design of our future off-shore man-made structures is required to avoid unnecessary repair cost. To assess the destructive forces due to the wave run-up, the maximum run-up height needs to be known. Although there are already some studies which relates to wave run-up, however, much is still not known about how the spacing of these vertical columns affect wave run-up. Basically, wave run-up is the vertical up-rush of water that occurs when an incident wave impinges on a partially immersed body. This paper presents the results of a physical model study of the run-up heights on two square arrays of vertical cylinders in deep water regular waves. The influence of wave steepness, wave height, wave length and cylinder spacing on run-up are investigated. The measured run-up values are compared with applicable theories and previous experimental studies. The results show that at different wave steepness and different spacing between the vertical columns does substantially affects the maximum run-up height, increasing the trend of the run-up value. We also learnt that for deep water waves, and at high wave steepness, it is necessary to have a higher order theory to represent the values of these run-ups as a linear theory is unable to represent these run-ups accurately. For these, previous studies have made used of the second order Stokes equation while in this paper, an exponential line, R2 is used to represent the goodness of fit of our experimental data.