Session: 06-05-01 Marine Hydrodynamics I

Paper Number: 100687

100687 - Hydrodynamic Response Analysis of Ultra-Deep Water FPSO System Using Ansys Aqwa, Wamit, and HydRA 

Offshore energy resources are essential to the growth of a future civilization. For offshore production, deep and ultradeep water fields are an ideal option. In general, floating platforms such as TLP, SPAR, FPSO, and semisubmersibles are the most viable solution for deepwater production. FPSOs are the most commonly installed platform compared to the other types. Implementing an offshore production platform in deep and ultradeep water requires a precise forecast of the structure's response. In this paper, the numerical hydrodynamic response analysis of an FPSO system has been performed using ANSYS Aqwa, Wamit, and HydRA.

             ANSYS Aqwa is a commercial software used widely in the offshore industry for offshore structure hydrodynamic and mooring analyses. WAMIT is the most efficient tool for examining wave interactions with offshore platforms and other structures or vessels developed by MIT, USA. HydRA (Hydrodynamic Response Analysis) is a code developed at IIT Madras that simulates marine and offshore structure linear and nonlinear dynamics in the ocean and fluid-structure interactions. It depicts the results without the use of commercial software. These computational tools are the numerical potential flow solver, which follows the boundary element method to solve the force and moment equations.

             The motion response study of the FPSO platform has been conducted at 2100m water depth and for two different load cases, ballast load and fully loaded condition, with varying wave headings of 0°, 30°, 90°, 120°, and 180°. The purpose of this paper is to demonstrate the importance of numerical software used for hydrodynamics analysis of offshore structures. This paper will compare hydrodynamic parameters such as added mass, radiation damping, and RAO (with and without viscous damping) for the three software mentioned above. The experimental investigation of the freely floating FPSO model under the fully loaded condition will be carried out in the wave basin, IIT Madras. The experiments will be conducted for regular, random, and directional waves with a wave period range of 0.9 to 2 secs. Both experimental and numerical analysis results will be compared and validated. Finally, the compatibility of the numerical tools used for the hydrodynamic analysis will be discussed.           

Presenting Author: Krishnamoorthy Sridhar Indian Institute of Technology, Madras

Presenting Author Biography: He is a PMRF Doctoral Research scholar at the department of ocean engineering, Indian Institute of Technology Madras (IITM). He is doing research in the field of Floating Structural Concepts with Mooring and Riser Systems. Before joining IITM, he did a master's degree in Structural Engineering at A. C Government College of Engineering & Technology (ACGCET) karaikudi, Tamilnadu. A bachelor's degree in Civil Engineering from the University College of Engineering (UCE-Pattukkottai), Anna University. His research interests include structural analysis, Fluid-structure interactions, Hydrodynamics of Deepwater platforms, Coupled analysis of Mooring & riser systems, etc.

Apart from academics, he also exhibited his interest in co-curricular and extracurricular activities. He is an active student member of ASCE, ASME, and MTS and an associate member of RINA in the United Kingdom.

Authors:

K. Sridhar Indian Institute of Technology, Madras
S. A. Sannasiraj Indian Institute of Technology, Madras
R. Sundaravadivelu Indian Institute of Technology, Madras.