Numerical Calculation Of Hydrodynamics Of Three Dimensional Ship Hull Based On B-Splines

The cause of shipping must have a flourish development with the access to World Trade Organization and further reformation of economy system of our country. It is imperious need to understand the hydrodynamic forces acted on ship hull while the amount of ships in the sea-routes is increasing. These forces, especially the changing tendency of hydrodynamics when the two ships are meeting or a ship is passing a pier are of great importance to avoid the shipwrecks such as ship collision.Computational Fluid Dynamics (( FD) provides a condition for numerically simulating ship fluid flow field with the development and commercialization. CFD has its superiority and potential for developing with contrast to trial method. Incorporating the non uniform rational B spline (NURBS) which is the only definition of the form of industry products, the author selects the method of B spline to do the numerical computation research work of the hydrodynamics of three dimensional ship hull based on the reading and analysis of the documents about hydrodynamics, especially the interaction hydrodynamics. The method not only brings a new method for the calculation of the hydrodynamics of ship hull, but also provides an interface effect having no sew between the ship Computer Aided Design (CAD) and ship Computational fluid Dynamics (CFD).As a fundamental work of the numerical calculation, Chapter 2 geometrically sculpts the body lines and surface of ship hull using an interactive method and adopts the format of NURBS. The vertexes are directly used by the latter numerical calculation, which avoids the tedious work of data inputting and processing in the traditional CFD programs. In order to verify the feasibility of the present method, Chapter 3 takes the fluid flow of sphere, cylinder and the additive mass of two spheres as three examples, finishes the calculation by disposing the source or sink whose strength is expressed as the format of NURBS and emphatically the processing of the singular integral. It can be drawn from the comparison of the results of present method andthe theoretical solution, i.e. a good precision can be gotten under a few collocation points with the method. Chapter 4 computes the wave-making resistance, the 3D wave figure and its contour figure of Wigley ship and makes satisfying results.Chapter 5 directly sets out from the Green formulae of velocity potential due to the existence of lifting force, adopts an approximate Kutta condition and firstly calculates the maneuvering hydrodynamics of a Wigley ship with an attack angle using the present method of B spline. The precision of the numerical results at a small attack angle is better than that at a big attack angle. It may owe to the approximate Kutta condition adopted here. Chapter 6 and 7 are divided into two parts for the interaction hydrodynamics, i.e. the quasi-steady and the unsteady calculation fully in time domain. The results qualitatively and quantitatively agree with the trial results published in the documents. These not only provide theoretical basis for the motion mechanism of ship collisions, but also give the decision support on avoiding the ship collisions.Chapter 8 simulates the ship maneuvering motion of turning and zigzag test and takes into account the effect of water depth on ship maneuverability by use of the Maneuvering Model Group (MMG) of Japan. The main aim is to satisfy the need such as developing the maneuvering simulator of freshwater, the dynamic demonstration of avoiding ship collisions. Finally, Chapter 9 summarizes the whole paper and puts forward the further research interests.