Numerical analysis on ship to ship gap influence on resonance

• Main Author: Loh, Kelvin Chee Sing
• Other Authors: Ng Yin Kwee, Eddie
• Format: Theses and Dissertations
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/75710
• Institution: Nanyang Technological University

The advantage of ship to ship transfer, especially when berthing of VLCC and ULCC is difficult, is cost effectiveness. However, such operations are associated with safety risks such as hull damages, personnel safety risks and pollution due to operation accidents. Therefore, it is imperative to understand the nature and effects of the environmental factors especially involving sea waves during ship-to-ship operations. Two major aims are outlined in this dissertation: to understand how the gap distance between the ships influences the dependent variables such as wave elevation and to further scrutinise the hydrodynamic interactions regarding this phenomenon. Numerical simulation is firstly done to verify the Airy wave model at wave amplitude 1.05m and period 5s. However, wave pattern unexpectedly exhibit nonlinear characteristics such as sharp crests and flat troughs. This is followed by a ship to ship numerical study with conditions similar to Xu et al. (2014) numerical study at gap widths of 3m, 6m and 12m with 5 equal distance data points at the gap region. The results then show that narrower gap width correlates strongly with larger wave elevations and smaller periods. Velocity vectors and pressure contours from the numerical study also show higher values during gap resonance motion. Next, to establish a local baseline for the findings, Li et al. (2016) barge to barge numerical study is replicated. It is observed that the wave elevation values from this replicated study agrees poorly with what was found in Li et al. (2016) study where replicated study show a lower trend than the original. All numerical computations in this dissertation are done using ASPIRE1 HPC with 168 core processors.