This paper briefly reviews the history and development of compounds, tiltrotors and hingeless rotors. Largely through a quirk of history, the compound has been neglected for over three decades. The mission performance potential of the compound is re-examined based on basic aerodynamic principles and by surveying recent NASA and Army mission design studies. A rational case can be made that the c...

The compatibility between a composite beam cross-sectional analysis based on the variational asymptotic approach, and a helicopter rotor blade model which is part of a comprehensive rotorcraft analysis code is examined. It was found that the finite element cross-sectional analysis code VABS can be combined with a moderate deflection rotor blade model in spite of the differences between the form...

The paper describes an unusual C beam discretization based on the finite volumes concept. The formulation is developed in the linear (linearised) case first; eventually a non-linear multi-body approach to the same problem, based on previous works [9], is presented. The formulation is generalised to the piezo-electric beam in both cases, with reference to work [10]. Some applications are outline...

The influence of flow separation location on eigenmode synchronization and phonation onset was investigated in a two-dimensional, aeroelastic, continuum model of phonation. A linear stability analysis showed that flow separation played a critical role in initiating eigenmode synchronization and phonation. For a given glottal configuration, a small variation in the flow separation location along...

In this work, an aeroelastic prediction framework is formulated by blending control-oriented techniques that consist of linear fractional transformation representation, identification of nonlinear operators, and stability boundary prediction for both flutter and limit-cycle-oscillation phenomena. The final product is an efficient tool devised to identify, characterize, and predict flutter/limit...

A three-degrees of freedom (3-DOF) coupled numerical simulation technique for synchronously extracting 18 aerodynamic derivatives of bridge decks is proposed and evaluated in this study. Computations are performed with a finite volume unstructured computational flow dynamics (CFD) solver using two-dimensional (2D) hybrid meshes with fine near-wall resolution. The accuracy of the numerical model...

Wind turbines are complex structures and their dynamics vary significantly in operation, in comparison to that under stand still (parked) conditions. Presence of rotational loads and considerable aeroelastic effects makes it difficult to apply conventional system identification techniques to wind turbines. Operational Modal Analysis (OMA) is a technique of determining dynamic characteristics of...

In 1957 the slender-delta type of configuration had been adopted in the U.K. as the most promising for a supersonic transport aircraft designed to cruise at about M = 2.0, and by 1959 one or two exploratory studies of the aeroelastic behaviour of such layouts had been made. Professor Etkin now suggested a mode of attack on the steady and quasi-steady aeroelastic problems, whereby such an aircra...