The underwater noise prediction from marine propellers: An essentially nonlinear problem

This paper aims to numerically demonstrate that the underwater noise generated by a marine propeller is an essentially nonlinear problem and that, unlike the analogous aeronautical configurations, the nonlinear flow noise sources play a dominant role independently of the low rotational speed of the blade. To this aim the prediction of the thickness noise component only (in air) is carried out on two typical blade models corresponding to a helicopter rotor and a marine propeller, in order to assess how the main structural and geometrical differences between these two bodies (the aspect ratio, the twist and thickness distribution along span) can affect the resulting noise in the far field.