Acoustic signature reduction, modulation and control

In the present study the problem of the ship signature is dealt with considering the main perturbation sources that have a relevance on the propeller induced noise and vibrations. Specifically the following aspects that cause major effect on the hydroacoustic and propulsive performance of a marine propeller will be discussed: (i) the effect of the inflow, (ii) the contribution of the wake evolution and breakdown mechanisms, (iii) the propeller-rudder/propeller-strut interaction in conventional and podded propulsors. The results presented in the paper are part of research activities carried out by INSEAN, most of them supported by the Italian Navy. In this framework INSEAN has developed and implemented a number of advanced experimental and numerical tools, pioneering sometimes, which have aimed at probing into the complex problem of the hydrodynamic and hydroacoustic performance of a marine propeller.