A study of three types of flight maneuvers, namely arrested descent, turns, and roll-reversal maneuvers, were examined using a rotorcraft aeroacoustics prediction model. The components of the model comprised a utility helicopter flight dynamic model, a time-accurate free-vortex rotor wake model, and a maneuvering rotor noise prediction code. All rotorcraft motions and rigid body blade motions were included in the respective models. The rotor wake geometry and its development during the various flight maneuvers is described. In a transient maneuver, the rotor wake behavior is shown to be relatively complicated and in some cases the tip-vortices "bundle" together. The interaction of the tip vortices with the rotor blades creates a significant increase in levels of the impulsive noise, but primarily when the interaction of the nearly parallel to the blade. When a "bundle" of tip vortices interacts with the rotor in a near-parallel interaction, a very large increase in impulsive noise is observed over a very large region under the rotor.
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