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ItemAdvanced marine vehicle products database preliminary design tool(University of Hawaii at Manoa, 2003-08)The term advanced marine vehicle encompasses a broad category of ship designs typically referring to multihull ships such as catamarans, trimarans and SWATH (small waterplane area twin hull) ships, but also includes hovercrafts, SES (surface effect ships), hydrofoils, and advanced monohulls. This study develops an early stage design tool for advanced marine vehicles that provides principal particulars and additional parameters such as fuel capacity and propulsive power based on input ship requirements. This is accomplished by compiling a product database of existing advanced marine vehicles for the development of relationships between ship characteristic parameters. The relationships are analyzed using both the multiple regression analysis and a neural network. Because of the scatter of the data, the first order or linear multiple regression analysis is adopted. The neural network, on the other hand, is a non-linear learning tool that uses existing ship parameters to predict future ship designs. The results are compared with the actual ship parameters to validate the preliminary design tools. The Maui High Performance Computing Center has developed a geographic information system interface for the statistical tools and databases with the additional capabilities to analyze ocean wave environment for the definition of ship design requirements.
ItemAnalysis of harbor oscillation with a boussinesq model(University of Hawaii at Manoa, 2003-08)Seiches or long-wave oscillations in harbors are normally the result of nonlinear interactions within groups of narrow-banded wind waves and swell. These oscillations may cause excessive vessel motions and disrupt loading and unloading operations at port facilities. Accurate prediction of harbor oscillation patterns is therefore an important aspect in harbor design. Most previous studies have used linear models to predict these nonlinear oscillation behaviors. This study uses an extended Boussinesq model that is applicable from deep to shallow water and takes into account the generation mechanism of these oscillations along with their interaction with the wind waves or swell. The finite difference model utilizes a predictor-corrector scheme to march the solution forward in time. It has a moving boundary algorithm to account for wave swashing, thereby allowing the correct boundary condition to be imposed at shorelines. The model is applied to examine the natural oscillation modes at Barbers Point Harbor and Kahului Harbor located on the West and North shores of Oʻahu and Maui respectively. The computed responses at each harbor are compared with previous linear model results and data gathered from pressure sensors. The analysis shows that harbor oscillation is primarily excited by infragravity waves, which can be simulated by a Boussinesq model.