NUMERICAL ALGORITHMS FOR SLENDER BODIES WITH VORTEX SHEDDING AND DENSITY STRATIFICATION

The correct prediction of the hydrodynamic performance of ships is an important factor in hull form design. This paper presents efficient nu merical algorithms for the calculation of the hydrodynamic forces acti ng on slender ships. ''Parabolized'' slender-body theory, generalized to accommodate oblique forward ship motion, transforms a three-dimensi onal ship wave potential problem into a series of two-dimensional wave -maker problems in the ship frame. The computation starts at the bow s ection and progresses by marching in steps along the ship length. The application of this procedure for handling surface and interfacial wav es created by a prolate spheroid in a density stratified flow is given ; results are compared with published experimental results. The parabo lized formulation, with the nonlinear free-surface conditions, is used for calculating the wave pattern and wave resistance of a Wigley hull at zero angle of incidence and at an angle of incidence of ten degree s. A hybrid boundary-element, discrete vortex procedure is used to cal culate the potential flow. The strength of the vortices and their deve lopment is obtained as a part of solution. The numerical results are c ompared with published experimental and numerical results.