Theory And Computation Software Of Ship Green Function Near Field

With the rapid development of economic globalization, the proportion of maritime transport sharply raised in the whole transportation industry. However, the violent oscillation of ship while moving over water, may not only influences the ship velocity, but also result in ship deformation and unpredictable consequences. In a word, the project, which researches on ship’s higher operational efficiency in the ocean, and design of better seakeeping ship, enjoys great significance for ship safe navigation and economic operation.In this paper, the two dimensional near field Green function is solved. According to the second-order partial differential equation and boundary conditions of Green function, this paper firstly uses Fourier transform to obtain first-order differential equation. Secondly, it gets Green function’s Fournier transform expression by using solutions’ continuity and the properties of generalized function S. Thirdly, the computational formula of Green function is obtained by using properties of infinite integral. Finally, according to the Green function expression in this paper, the properties and derivative of Green function are analyzed, and the particular values of Green function are computed.This paper researches on Green function calculation model with infinite integral limit and singular points and creates the composite and fast numerical method, that’s using a couple of real parameters or single complex parameter to express Green function, choosing single line in the complex plane and calculating the Green function, and obtaining the value on the plane. Then use function interpolation method creates fast Green function calculation method. Next, the paper analyzes error of Green function and the relationship between real and complex part in the infinite integral with singular points, and compute the range of parameter and error distribution.Above all, according to the computation of Green function, this paper has designed a calculating system of Green function, discussed the system’s structure, function and product specification, compiled a series of Green function database calculating software in different languages, and analyzed merits and demerits for further research in the future.