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...

Structural motion induced aerodynamic forces on bridges are customarily characterized in terms of flutter derivatives. Considerable effort has been extended to refine the procedure to identify flutter derivatives of bridge decks using spring-suspended twodegree-of-freedom bridge deck section models in wind tunnels. In this context, techniques and implied approximations employed in the literatur...

Atrial flutter in the donor part of orthotopic heart transplants has been reported and successfully treated by radiofrequency ablation of the cavotricuspid isthmus, but mapping and ablation of atypical flutter circuits may be challenging.(1) Entrainment mapping has been used in combination with activation mapping to define the mechanism of atypical atrial flutter. Here, we report a case where c...

This study presents a framework with closed-form solutions for the bimodal coupled bridge aerolastic system, and points out the control parameters which critically influence the generation of inter-modal coupling and aerodynamic damping. Accordingly, this information helps in developing a guideline for the selection of most important structural modes in a coupled flutter analysis. The role of e...

The benchmark active controls technology and wind tunnel test program at NASA Langley Research Center was started with the objective to investigate the nonlinear, unsteady aerodynamics and active flutter suppression of wings in transonic flow. The paper will present the flutter suppression control law design process, numerical nonlinear simulation and wind tunnel test results for the NACA 0012 ...

This work explores the use of tow steered composite laminates, functionally graded metals (FGM), thickness distributions, and curvilinear rib/spar/stringer topologies for aeroelastic tailoring. Parameterized models of the Common Research Model (CRM) wing box have been developed for passive aeroelastic tailoring trade studies. Metrics of interest include the wing weight, the onset of dynamic flu...

BACKGROUND Although most ablative procedures undertaken for common atrial flutter target the inferior right atrial isthmus, comparative studies of the morphology of this area are lacking. Our study examines its angiographic anatomy, making correlations with postmortem specimens, to provide a better understanding of the anatomic substrate of this arrhythmia. METHODS AND RESULTS The gross morph...

Large prospective, randomized, controlled trials have demonstrated the efficacy of anticoagulation for the prevention of cardioembolic stroke in atrial fibrillation. Anticoagulation with warfarin is associated with a 70% relative risk reduction in thromboembolic events for certain high risk groups and this can be accomplished without a substantive risk of major bleeding (1–3). Whether chronic a...