Parametric investigation of the effect of hub pitching moment on blade vortex interaction (BVI) noise of an isolated rotor

Carlos Malpica, Eric Greenwood, Ben Sim

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

At the most fundamental level, main rotor loading noise is caused by the harmonically-varying aerodynamic loads (acoustic pressures) exerted by the rotating blades on the air. Rotorcraft main rotor noise is therefore, in principle, a function of rotor control inputs, and thus the forces and moments required to achieve steady, or "trim", flight equilibrium. In certain flight conditions, the ensuing aerodynamic loading on the rotor(s) can result in highly obtrusive harmonic noise. The effect of the propulsive force, or X-force, on Blade-Vortex Interaction (BVI) noise is well documented. This paper presents an acoustics parametric sensitivity analysis of the effect of varying rotor aerodynamic pitch hub trim moments on BVI noise radiated by an S-70 helicopter main rotor. Results show that changing the hub pitching moment for an isolated rotor, trimmed in nominal 80 knot, 6 and 12 deg descent, flight conditions, alters the miss distance between the blades and the vortex in ways that have varied and noticeable effects on the BVI radiated-noise directionality. Peak BVI noise level is however not significantly altered. The application of hub pitching moment allows the attitude of the fuselage to be controlled; for example, to compensate for the uncomfortable change in fuselage pitch attitude introduced by a fuselage-mounted X-force controller.

Original languageEnglish (US)
Title of host publication72nd American Helicopter Society International Annual Forum 2016
Subtitle of host publicationLeveraging Emerging Technologies for Future Capabilities
PublisherAmerican Helicopter Society
Pages188-201
Number of pages14
ISBN (Electronic)9781510825062
StatePublished - Jan 1 2016

Publication series

NameAnnual Forum Proceedings - AHS International
Volume1
ISSN (Print)1552-2938

All Science Journal Classification (ASJC) codes

  • Engineering(all)

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