This paper introduces an adaptive flutter suppression control algorithm which is based on the iterative estimate of the aeroelastic plant and design of the feedback controller. In this algorithm, the dual-Youla parametrization is implemented as an essential part to estimate the open loop aeroelastic model from the closed loop experiment. The advantage of utilizing the dual-Youla parametrization...

Flutter of the auricles may be associated with either a regular or an irregular ventricular rate. The former occurs as a rule in the untreated patient, the latter as a result of digitalis therapy. An attempt was made to explain the irregular ventricular response in auricular flutter as a result of a conduction disturbance similar to that seen in sinus rhythm with second degree A-V block charact...

A ground vibration test can be used to obtain information about structural dynamics that is important for flutter analysis. Traditionally, this information— such as natural frequencies of modes—is used to update analytical models used to predict flutter speeds. The ground vibration test can also be used to obtain uncertainty models, such as natural frequencies and their associated variations, t...

Structural instability caused by self exciting aerodynamic forces (flutter) can be used as an effective input source for small scale energy harvesters. The self exciting aerodynamic force exerted on a T-shape cantilever causes periodic vibration, which can be converted into electric power through an electromagnetic transducer. Due to the complexities inherent in the fluid-structure interaction ...

This thesis focuses on deriving algorithmic frameworks for the control of Aerodynamic Phenomena. The application of one such control law to the control of Flutter is discussed in detail. Flutter is an aero-structural instability that arises due to the adverse transfer of energy between the airplane structure and the surrounding fluid. CFD is now a mature technology and can be used as a design t...

Two rectangular wings of aspect ratio 4 were flutter tested in a supersonic wind tunnel at Mach numbers 1·6 and 2·0 using a technique in which a structural stiffness was varied to give flutter at the Mach number. The results are in reasonable agreement with calculations using theoretical three-dimensional derivatives and arbitrary wing modes, though in general the calculated critical stiffnesse...

An interactive computer program was developed for wing flutter analysis in the conceptual design stage. The objective was to estimate the flutter instability boundary of a flexible cantilever wing, when well defined structural and aerodynamic data are not available, and then study the effect of change in Mach number, dynamic pressure, torsional frequency, sweep, mass ratio, aspect ratio, taper ...

Males in the 'bee' hummingbird clade produce distinctive, species-specific sounds with fluttering tail feathers during courtship displays. Flutter may be the result of vortex shedding or aeroelastic interactions. We investigated the underlying mechanics of flutter and sound production of a series of different feathers in a wind tunnel. All feathers tested were capable of fluttering at frequenci...

OBJECTIVE The aim of this study was to evaluate the cause and treatment of atrial flutter after coronary artery bypass grafting (CABG). METHODS Between July 1999 and July 2000, 96 CABGs were performed at the Cardiovascular Center of Aichi Prefectural Owari Hospital. We compared two groups of patients: those with atrial flutter after CABG (group A) and those without atrial flutter (group B). ...

Here, we report a stable and predictable aero-elastic motion in the flow-driven energy harvester, which is different from flapping and vortex-induced-vibration (VIV). A unified theoretical frame work that describes the flutter phenomenon observed in both "stiff" and "flexible" materials for flow driven energy harvester was presented in this work. We prove flutter in both types of materials is t...