Flap-lag-torsion stability in hover and forward flight with three-dimensional wake

Manjunath, AR and Chunduru, SJ and Nagabhushanam, J and Gaonkar, GH (1996) Flap-lag-torsion stability in hover and forward flight with three-dimensional wake. In: AIAA Journal, 34 (1). 18-28 .

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Abstract

The contributions of full-wake dynamics in trim analysis are demonstrated for finding the control inputs and periodic responses simultaneously, as well as in Floquet eigenanalysis for finding the damping levels. The equations of flap bending, lag bending, and torsion are coupled with a three-dimensional, finite state wake, and low-frequency (<1/rev) to high frequency (>1/rev) multiblade modes are considered. Full blade-wake dynamics is used in trim analysis and Floquet eigenanalysis. A uniform cantilever blade in trimmed flight is investigated over a range of thrust levels, advance ratios, number of blades, and blade torsional frequencies. The investigation includes the convergence characteristics of control inputs, periodic responses, and damping levels with respect to the number of spatial azimuthal harmonics and radial shape functions in the wake representation. It also includes correlation with the measured lag damping of a three-bladed untrimmed rotor. The parametric study shows the dominant influence of wake dynamics on control inputs, periodic responses, and damping levels, and wake theory generally improves the correlation.

Item Type:	Journal Article
Publication:	AIAA Journal
Publisher:	American institute of aeronautics and astronautics
Additional Information:	Copyright of this article belongs to American institute of aeronautics and astronautics.
Department/Centre:	Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited:	26 Apr 2011 05:32
Last Modified:	26 Apr 2011 05:32
URI:	http://eprints.iisc.ac.in/id/eprint/37188

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