Hybrid Model for Cavitation Noise Spectra Prediction

In the latest years, models combining physical knowledge of a phenomenon and statistical inference are becoming of much interest in many real world applications. In this context, ship propeller underwater radiated noise is an interesting field of application for these so-called hybrid models, especially when the propeller cavitates. Nowadays, model scale tests are considered the state-of-the-art technique to predict the cavitation noise spectra. Unfortunately, they are negatively affected by scale effects which could alter the onset of some interesting cavitating phenomena respect to the full scale propeller; as a consequence, for some ship operational conditions it is not trivial to correctly reproduce the cavitation pattern in model scale tests. Moreover, model scale tests are quite expensive and time-consuming; it is not feasible to include them in the early stage of the design. Nevertheless, data collected during these tests can be adopted in order to tune a data-driven model while the physical equation describing the occurring phenomenon can be used to refine the prediction. In this work, the authors propose a hybrid model for the prediction of ships propeller underwater radiated noise, able to exploit both the physical knowledge of the problem and the real data obtained from cavitation tunnel experiments performed on different propellers in different working conditions. Results on real data will support the validity and the effectiveness of the proposal.