Maneuvering Hydrodynamic Forces Calculated Using Circulation Retension Characteristics

Abstract

Assuming that a ship hull can be replaced by a rectangular flat wing, a simplified method is examined for calculating the maneuvering hydrodynamic forces and shedding angles of the trailing vortices in shallow water. This method is based on the INOUE's method using infinite images with respect to bottom. This study takes into account bound vortices retained at the wing tip in shallow water condition. If the fluid behaves ideally, vortices bridging the gap must be distributed over the tip-clearance. In this report, influence of the vortices remaining in the gap on predicting the hydrodynamic forces and the shedding angles is discussed. As a result, it is indicated that the vortices distributed in the gap cause decrease in the shedding angles and the hydrodynamic forces. However, the changein the hydrodynamic forces is slight compared with that in the shedding angles. It may be concluded that taking account of the vortices in the gap is useful for obtaining better agreement between calculated values and experimental values for both the hydrodynamic forces and the shedding angles.