TANI , Giorgio

The propeller performances and in particular the non-stationary cavitating behavior and its side effects, i.e. pressure pulses and radiated noise, are strongly dependent on the ship wake field. Many different predictive methods are available, however in many cases predictions are still performed on the basis of semi-empirical approaches, whose...

The continuous development of design tools and analysis procedures has allowed propeller performances to increase progressively during years following more and more stringent design requirements . High propeller efficiency and avoidance of erosive cavitation are considered nowadays basic requests for a well designed propeller. However this may...

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In present work, an acoustic characterisation of the University of Genoa cavitation tunnel is presented, with the aim to obtain suitable transfer functions in order to take into account (at least partially) the effects of the confined environment, particularly important for small-scale facility like the one considered. The acoustic...

Ducted propellers, in decelerating duct configuration, may represent a possible solution for the designer to reduce cavitation and its side effects, i.e. induced pressures and radiated noise; however, their design still presents challenges, due to the complex evaluation of the decelerating duct effects and to the limited amount of available...

The interest for cavitation noise studies and prediction is increasing in the field of naval architecture, mainly because of attention to environmental issues. Model scale tests in cavitation tunnels are commonly considered as one of the most effective tools for cavitation noise studies. However, despite being carried out since long time, model...

The prediction of propeller induced pressure fluctuations and underwater radiated noise is a subject of great and increasing interest in marine engineering. Nevertheless, the full-scale prediction of these negative effects, even though based on dedicated model scale tests represents still a challenging task. This is due to different phenomena,...

In this work the problem of underwater radiated noise emitted by cavitating propellers is addressed, considering the case of single screw ships. To this aim, a series of experimental results obtained in model and full scale is presented. The analysis of results reported allows to discuss the effect of the surrounding ambient in model scale...

A growing attention has been recently devoted to the impact of the underwater noise field generated by shipping activities on the marine fauna. A key aspect for the quantification of such impact is a proper model of the source levels radiated from the vessels. At a first level of approximation, simplified formulations based on a small number of...

The present study makes use of microphonic and accelerometric measurement techniques to identify the cause of an anomalous behavior of the driveline of a cavitation tunnel for marine propellers. Such a testing facility makes possible the fluodynamic and acoustic characterization of in scale models of naval propellers. To get significant data it...

The present paper deals with the side effects of propellers cavitation, i.e. pressure pulses and radiated noise. These effects are gaining more and more importance for commercial ships for different reasons. Pressure pulses significantly affect comfort onboard, thus their reduction is of utmost importance for all ships carrying passengers. As...

Marine propellers design requirements are always more pressing and the application of unusual propulsive configurations, like ducted propellers with decelerating nozzles, may represent a valuable alternative to fulfil stringent design constraints. If accelerating duct configurations were realized mainly to increase the propeller efficiency in...