Analysis of rotor noise using LES*

The flow field of a five-bladed marine propeller operating at design condition, obtained using large eddy simulation (LES), is used to calculate far-field sound. Three acoustic formulations are used: a point force dipole model, Curle acoustic analogy, and Ffowcs--Williams and Hawkings acoustic analogy. Each formulation is derived from the Navier--Stokes equations and the effects of the underlying assumptions are examined. The acoustic surface for the Curle and Ffowcs--Williams and Hawkings acoustic analogies is chosen to be the propeller; the propeller is split into a collection of acoustically compact radial strips. The computed sound is analyzed and the physics of sound generation is inspected. Results including far-field sound spectra and directivity will be discussed.