Ng Cheng Yee ¹, Siti NorAdha Binti Tuhaijan ², Ligar A. Pangestu ²

Affiliations
1 Department of Civiland Environmental Engineering, University Technology PETRONAS, 32610 Seri Iskandar,PerakMalaysia, MY
2 Department of Civiland Environmental Engineering, University Technology PETRONAS, 32610 Seri Iskandar,, MY

Abstract

Objectives: To determine the hydrodynamic coefficients; drag (Cd) and inertia (Cm), for short-crested waves exerted on vertical cylinder. Methods/Statistical Analysis: An experimental study on hydrodynamic coefficients of the top-fitted vertical cylinder subjected to short-crested waves is presented. The model tests were carried out in the wave tank of Offshore Laboratory of University Technology PETRONAS, Malaysia. In this study, the model testwas conducted by using two sets of vertical cylinder with diameter, 16 mm and 48 mm, which were subjected to four series of short-crested waves based on four different locations in Malaysian offshore region.The wave forces acting on the cylinder were recorded by using wave force sensor. The post processing data was carried outby considering The Least Square Method. The results were compared with the existing recommended hydrodynamic coefficients in the PETRONAS Technical Standard (PTS). Findings: The hydrodynamic coefficients for short-crested wave of a vertical cylinderwere obtained. The results showed that the experimental hydrodynamic coefficient values are 30 % to 45 % lowerthan the recommended hydrodynamic coefficients adopted by PTS. Application/Improvements: The hydrodynamic coefficients values obtained from this experimental investigationhave ensured the possibility of designing an economical and optimum design of offshore platforms could be achieved.

Keywords

Drag Coefficient, Inertia Coefficient ,Short-Crested Wave

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Phuor Ty ¹, Indra S.H. Harahap ¹, Ng Cheng Yee ¹

Affiliations
1 Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Tronoh 31750, Perak, MY

Abstract

Jack-up is a type of movable offshore structure that comprises of foundation, leg and hull. Its analysis requires finite element analyses to generate a reliable structural responses under different geometrical configurations and loading types, especially during the conceptual phase. In this phase, the objective is to seek a vigorous and economical structural configuration. This paper presents the application of an object-oriented approach in developing finite element software for jack-up analysis within the MATLAB environment. The objective is to update the cycle of data preparation and analysis. In this finite element tool, with a simple command, any changes in the jack-up element such as material, basic geometrical dimensions and loading types are easily changed. This paper also provides a further illustration of the usefulness and potential of the object oriented perspective. A detail discussion of the structural analyzer sub system with regard to structural optimization and structural design has been additionally specified. Examples are given for application for creation of different configurations of jackup structures.

Keywords

Finite Element Method, Jack-Up, Object-oriented Approach.

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