Calculation Of Hydrodynamic Forces On A Ship In Oscillating Motion With Forward Speed

With the rapid development of computer science and technology over the past twenty years, computer has found wide application in hydrodynamics and related subjects, and many numerical schemes have been successfully developed. This makes Computational Fluid Dynamics (CFD) becoming more and more mature and powerful. The application of CFD in ship hydrodynamics results in an important branch– ship CFD, i.e. Numerical Towing Tank. Numerical Towing Tank technology employs CFD methods to simulate the flow around ship, so that the ship hydrodynamic performances can be predicted as by the model test in physical tank. Numerical Towing Tank technology is the key and high technology in ship engineering, and provides a novel method to study ship hydrodynamics. In contrast to the theoretical and experimental methods, Numerical Towing Tank method has some special merits and potential in predicting ship hydrodynamics. Nowadays, development and application of Numerical Towing Tank has become one of the focuses in naval and ocean engineering.Under this background and supported by the National Natural Science Foundation of China and the Natural Science Foundation of Shanghai, this thesis, aiming at developing Numerical Towing Tank independently, has developed a 3D higher order panel method for ship Hydrodynamics based on potential theory and Non-Uniform Rational B-Spline (NURBS). The numerical scheme is utilized for solving ship steady wave-making problem and unsteady radiation problem with forward speed effects.Panel methods are common and efficient numerical methods for potential problem, among them the higher order panel method has the advantage that the body geometry and singularity strength distribution over the boundary surface are continuous up to some order. Using Rankine source as the Green function, this thesis has developed a 3D higher order panel method for solving potential problem in ship hydrodynamics. Firstly, the boundary value problems for steady wave-making potential and unsteady radiation potential with forward speed are established for a ship in unrestricted deep water, where the potential in the flow field is represented by Rankine sources distributed over the ship wetted surface and the free surface. The boundary surfaces are described accurately by using NURBS, whereas the unknown singularity strength...