Active whirl flutter control through dynamic wind tunnel experiments and modelling

Abstract

Whirl flutter aeroelastic instability is a well-known limiter of performance in current generation tiltrotors, and as such, its study is of particular interest for future rotorcraft generations. This paper presents two integrated systems aiming to facilitate novel analysis of the whirl flutter phenomenon and its alleviation through active mini-tab control: a bespoke experimental rig, and a complementary numerical model. This is the first experimental and numerical investigation of active whirl flutter control with a promising, and practically realisable flow control technology. The experimental rig is shown to be capable of producing dynamic motion comparable to documented XV-15 flutter, while LQR analysis of the reduced-order model suggests the feasibility of linear control, which offers unique advantages over nonlinear control for practical implementation of the technology. A mutually beneficial relationship is established between physical testing and numerical investigation enabling state of the art data collection and analysis.