Experimental Characterization of Two CP Propellers at Different Pitch Settings, Considering Cavitating Behaviour and Related Noise Phenomena

With the introduction of numerical methods which can provide a highly reliable assessment of propeller characteristics, not only in correspondence to the usual design conditions but also to off-design conditions, propeller design has evolved significantly in the last years. Nevertheless, problems still exist if “very offdesign conditions” are considered, and if interest is posed in cavitation-related problems, such as radiated noise. Interest in radiated noise phenomenon is constantly increasing, no longer involving only naval vessels, but now also affecting the design of other “high added value ships”, such as cruise ships and mega yachts, for which questions of comfort and the environmental impact are key elements. One of the most significant problems related to radiated noise is the rather low amount of experimental data available, and this is particularly significant for CPP propellers at off-design conditions. In the present paper, the experimental characterization of two alternative designs of a CP propeller in terms of usual mechanical characteristic, cavitation and radiated noise, is presented. The experimental campaign has been conducted considering two very different pitch settings, allowing for analysing propeller behaviour, also in correspondence to very off-design conditions.