Dario Bruzzone

A Practical Method for the Prediction of Planing Craft Motions in Regular and Irregular Waves

Leisure boats market has constantly grown during the recent years, entailing an increasing need of design tools. This seems particularly urgent for seakeeping and hydrodynamic performance prediction in the field of planing boats. Numerical methodologies are almost consolidated instruments for conventional displacement ships, while some shortcomings are still to be faced and overcome concerning planing craft, due to the high complexity of the hydrodynamic problem. The present paper describes a simplified methodology for the prediction of pitch, heave and roll motions of a planing boat, in regular and irregular waves. In the formulation, a 2D approach is adopted, based on ‘momentum theory’; various aspects of the wedge-theory are used in order to model the sectional characteristics, with particular attention to the added mass. A validation of the proposed methodology concerning vertical motions is presented against data available in literature.Copyright

Nonlinear motions in head waves with a RANS and a potential code

In the last years, the employment of RANS codes for a wide range of naval architecture problems is grown, since this methodology is capable of reproducing physical behaviors that are generally neglected by other models. The paper presents the results of a set of numerical tests performed employing this methodology with the aim of verifying its capability in the solution of seakeeping problem. Several condition are analyzed varying the frequency of the incident wave and its amplitude, in order to catch nonlinear effects. The results are compared with the ones achieved by a weakly nonlinear procedure based on potential theory.

Co-operative investigation into resistance of different trimaran hull forms and configurations

Abstract This paper presents the results of a research program carried out on different trimaran hull forms and configurations suitable for medium size fast ferries. Resistance tests on large size scale models of the two different hull forms of main hull and outriggers, both isolated and combined in different configurations have been carried out at the towing tank of Naples University. For each isolated hull and trimaran configuration the total resistance and running trim have been assessed. Wave pattern analysis was also performed by experimental tests and by numerical computations, so that the influence of each resistance component has been highlighted. The results of this work could be used as a reference in trimaran hull design and optimization.