Broadband helicopter noise generated by blade wake interactions

摘要

Broadband noise from helicopter rotors is shown to be generated by the blades passing turbulence associated with the trailing tip vortices in the rotor wake. This happens when the trailing tip vortices are ingested into the rotor and during flight regimes such as level flight or low angles of ascent. To predict the broadband noise levels generated by this mechanism the details of the turbulent flow close to trailing tip vortices must be known accurately and the location of the vortices relative to the rotor blades must be specified.