Analysis of Main-Rotor-Wake/Tail-Rotor Interaction Noise
Analysis of Main-Rotor-Wake/Tail-Rotor
Continuum Dynamics, Inc.
PO Box 3073
Princeton, NJ 08543
Alan J. Bilanin (609-734-9282)
LaRC -- NAS1-18607
The importance of reducing the noise of the helicopter tail rotor has been recognized
for many years. However, both the prediction of tail rotor noise and the development
of low-noise designs have been impeded by a poor ability to simulate noise-generating
interactions between the main-rotor wake and the tail rotor. In many cases, even
the flight conditions leading to substantial interactions between the main-rotor
wake and the tail rotor have been difficult to determine. Recent advances in the
modelling of free-vortex wakes by the firm have generated tools that can generate
complete descriptions of the incident-vorticity field in the vicinity of the tail
rotor. In light of previous successes, it is anticipated that these tools can produce
a computational simulation capable of providing improved definition of interactions
between the main-rotor wake and the tail rotor and the resultant unsteady loads that
lead to strong acoustic emissions.
The Phase I effort successfully demonstrated that an advanced full-span model of
the main rotor wake could be incorporated in a novel scheme that permits high-resolution
descriptions of the tail rotor flow field to be reconstructed from preliminary, computationally
inexpensive simulations with coarse resolution.
Potential Commercial Application:
Potential Commercial Application: This analysis would aid rotorcraft designers in
meeting noise specifications for both civil and military helicopters and facilitate
research by government personnel in helicopter aero-acoustics.