DALIDA Task N4.IN2 - Noise evaluation for the propeller operating in the hull wake

This report is focused on the linear hydroacoustic analysis of a ship in a steady coarse and the evaluation of the scattering effects due to the mutual interactions between the hull and the propeller. To this aim, the Ffowcs Williams-Hawkings equation is solved for both a rotating and a translating body through the usual Farassat formulation 1A, thus limiting the analysis to the noise linear sources only. It will be shown how the linear (thickness and loading noise) components due to the propeller are predominant in a very circumscribed flow region. On the contrary, the hull scattered pressure due to the unsteady hydrodynamic loads induced by the propeller is quite relevant everywhere and plays an essential role (as a linear noise source) in the actual hydroacoustic far field.