Ship/model correlation study

Hopkins, Dwayne H. (2003) Ship/model correlation study. Masters thesis, Memorial University of Newfoundland.

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Abstract

Information regarding a ship's performance in seakeeping, propulsion and manoeuvring cannot always be reliably predicted using existing numerical models. In addition, methodology deficiencies in scaling physical model data to full scale can significantly compromise the results. There is very little detailed full scale ship data available to the researcher in the open literature for validation of physical modeling methodology and/or numerical models. With this design ambiguity in mind, Memorial University of Newfoundland (MUN) in collaboration with the Institute for Marine Dynamics (IMD) of the National Research Council (NRC) of Canada and Marineering Ltd. designed and performed a ship I model correlation study on a 40 m long research vessel, MN Louis M. Lauzier. Full scale sea trials were carried out on the 'Lauzier' in the Summer and Fall of 2001, while model scale research was performed on two different scale models (1:6 & 1:12) between August 2002 and June 2003. Numerical research was carried out concurrently using a computer generated replica of the 'Lauzier'. -- The powering, or propulsion, trials were performed to obtain the performance and propulsive characteristics of the vessel. I am able to correlate the model scale results to the full scale results to within 10% using the ITTC '78 power prediction. -- The manoeuvring trials provided information of the handling characteristics of the ship, for operational purposes. I am able to correlate certain parameters of each manoeuvre with a moderate level of accuracy: within 11% for the turning circle manoeuvres and within 15% for the zigzag manoeuvres. The analysis also showed that the Nomoto coefficients could be accurately calculated for the vessel from the zigzag manoeuvre. -- The seakeeping trials were carried out to define the seaworthiness characteristics of the ship by assessing the relationship between the motions of the ship and the related environmental conditions in which the ship was tested. With the correlation analysis, the model scale results compared relatively well to the full scale motions. In the particular cases where the peaks of the model scale motions were slightly shifted compared to the full scale motions, it can be attributed to the uncertainty of the wave direction from the analyzed full scale sea state. -- By carrying out this study, I am able to validate the methodologies of the above research bodies for physical modeling and their numerical ship performance prediction models, by using quality full scale ship data. Validation of the testing procedure allows the consortium to be more competitive in the international research industry.

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