Inclined-flow propeller hydroacoustics by the permeable Ffowcs Williams Hawkings equation

In this paper the noise hydrodynamically generated by noncavitating marine propellers in nonaxial flow condition is investigated. The permeable Ffowcs Williams and Hawkings Equation (FWH-P), solved by a Boundary Element Method (BEM), is used to radiate sound outward a suitable fictitious surface that encloses all the sources of sound related to the propeller and flow-field around it. To this aim, the fluctuating velocity and pressure field distributions required upon the permeable surface are obtained by a Detached Eddy Simulation (DES). For validation purposes, the acoustic signatures evaluated by the combined DES/FWH-P approach are compared with those directly computed by the hydrodynamic solver for observers placed in the near field.