Nature Of Ship Propeller Noise

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 noise still a challenging task. This is due to different phenomena, among which scale effects on cavitation and ship wake, confined environment and near field effects in model tests play an important role. the analysis of these problems is made difficult by the rather limited amount of available data from sea trials and to the complexities of the phenomena, most of which related to cavitation on the propeller blades, that are present in the measurements carried out in cavitation tunnels. In this paper, we examine the spectrum of noise from cavitation and non-cavitation propellers, and we examine the overall noise level measured in the band 100 Hz to 10 kHz based on the speed of the tip of the propeller and the number of blades for ships under 100 meters.