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This study uses measurements of pressure fluctuations of a full-scale ship for the calculation of the cavitation volume based on an acoustical model. The sound pressure signal had been recorded by pressure sensors mounted above the propeller of a 3600 TEU container vessel, combined with a synchronous tachometer signal from the propeller shaft. An acoustic monopole is used to model the unsteady sheet cavitation as a sound source. The analysis comprises intermediate high-pass filtering and integration followed by post-processing the resulting volume time signal. The cavitation volume evolution produced by consecutive blade passages shows well-recognisable steady growth and rapid collapse phases. By means of shape-dependend and time-synchronous sequencing and averaging methods, a representative volume signal of one blade passage has been deduced and several influential parameters have been identified. This allows modelling and manipulating the volume evolution and thus enables further investigations of the associated noise generation by propellers.

The European Marine Strategy Framework Directive requires European member states to develop strategies for their marine waters leading to programs of measures that achieve or maintain good environmental status (GES) in all European seas by 2020. An essential step toward reaching GES is the establishment of monitoring programs, enabling the state of marine waters to be assessed on a regular basis. A register for impulsive noise-generating activities would enable assessment of their cumulative impacts on wide temporal and spatial scales; monitoring of ambient noise would provide essential insight into current levels and any trend in European waters.

Low-frequency broadband shipping noise causes a growing concern for marine fauna together with the demand for noise reduction. Detailed analyses of the cavitation behaviour in the time domain serve as a prerequisite for steps toward quieter propellers. Underwater noise measurement data from the propeller of a full-scale container vessel are used for the analysis of the cavitation volume behaviour. Sequencing methods, polynomial models, and stochastic evaluation methods feeding Monte Carlo simulations of unsteady sheet cavitation are applied to identify the cause of an often observed, yet unexplained similarity in shipping noise spectra. Characteristic features of the volume evolution are identified to enhance the understanding of noise generation by sheet cavitation.