Based on Baba's assumption,the linearized free-surface boundary conditions at low speed are discussed in order to demonstrate the differences between Baba's and Dawson's free-surface boundary conditions.By...Based on Baba's assumption,the linearized free-surface boundary conditions at low speed are discussed in order to demonstrate the differences between Baba's and Dawson's free-surface boundary conditions.By using Fourier integral transfor- mation,a method of computing wave velocity potential ,which satisfies the boundary conditions of free-surface and hull surface,is presented.The solution of is found with the powerful technique of asymptotic expansions.With order comparison method,it is found that the hull surface boundary conditions can be neglected when only the ship wave resistance is concerned.The exact analytical solution of two-dimensional slow ship wave velocity potential is derived by neg- lecting hull effect.The results show that the inhomogeneous effect of free-surface is not negligible in the boundary value problems of slow ship velocity potential.展开更多
Despite of modern navigation devices, there are problems in navigation of vessels in waterways due to the geographical structures, disturbances in water, dynamic nature, and heavily environmental influenced sea traffi...Despite of modern navigation devices, there are problems in navigation of vessels in waterways due to the geographical structures, disturbances in water, dynamic nature, and heavily environmental influenced sea traffic. Even though all vessels are equipped with modern navigation devices, the accidents are reported caused by various reasons and mainly by human factor according to investigation. We propose an effective and efficient composition collision risk calculation method for finding the collision probability and avoiding the collision between ships in possible collision situations. The proposed composition collision risk calculation method at ship's position using combination of fuzzy and fuzzy comprehensive evaluation methods. The algorithm is straightforward to implement and is shown to be effective in automatic ship handling for ships involved in complex navigation situations. Experiments are carried out with indigenous data and the results show the effectiveness of the proposed approach.展开更多
文摘Based on Baba's assumption,the linearized free-surface boundary conditions at low speed are discussed in order to demonstrate the differences between Baba's and Dawson's free-surface boundary conditions.By using Fourier integral transfor- mation,a method of computing wave velocity potential ,which satisfies the boundary conditions of free-surface and hull surface,is presented.The solution of is found with the powerful technique of asymptotic expansions.With order comparison method,it is found that the hull surface boundary conditions can be neglected when only the ship wave resistance is concerned.The exact analytical solution of two-dimensional slow ship wave velocity potential is derived by neg- lecting hull effect.The results show that the inhomogeneous effect of free-surface is not negligible in the boundary value problems of slow ship velocity potential.
基金supported by ETRI through Maritime Safety & Maritime Traffic Management R&D Program of the MOF/KIMST (2009403, Development of Next Generation VTS for Maritime Safety)supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MEST) (No. 2011-0015009)
文摘Despite of modern navigation devices, there are problems in navigation of vessels in waterways due to the geographical structures, disturbances in water, dynamic nature, and heavily environmental influenced sea traffic. Even though all vessels are equipped with modern navigation devices, the accidents are reported caused by various reasons and mainly by human factor according to investigation. We propose an effective and efficient composition collision risk calculation method for finding the collision probability and avoiding the collision between ships in possible collision situations. The proposed composition collision risk calculation method at ship's position using combination of fuzzy and fuzzy comprehensive evaluation methods. The algorithm is straightforward to implement and is shown to be effective in automatic ship handling for ships involved in complex navigation situations. Experiments are carried out with indigenous data and the results show the effectiveness of the proposed approach.
