This study identifies the control parameters which critically influence the development of intermodal coupling and the generation of aerodynamic damping, based on closed-form solutions of bimodal coupled analysis of bridge aerolastic system. This information helps in developing a guideline for the selection of most critical structural modes in a coupled flutter analysis and in better interpreta...

OBJECTIVE To examine the effect of exercise on cycle length in atrial flutter. PATIENTS 15 patients with chronic atrial flutter. Seven patients were taking digoxin and six verapamil; two were not taking medication. METHODS All patients underwent bicycle ergometry. Flutter cycle length was measured at rest and at peak exercise. RESULTS Mean flutter cycle length increased from 245 ms to 256...

Atrial fibrillation and atrial flutter share a common reentrant mechanism. However, the relationship between these arrhythmias has not been systemically studied to date. To evaluate the degree to which these arrhythmias may alternate, consecutive Holter monitor recordings which showed fibrillation or flutter in 96 patients were reviewed. One half of the patients were studied after open-heart su...

sonic Unsteady Lifting Surfaces," AIAA Journal, Vol. 22, No. 2, 1984, pp. 179-186. Tewari, A., "Nonplanar Doublet-Point Method in Supersonic Three-Dimensional, Unsteady Aerodynamics," M.S. Thesis, Univ. of Missouri-Rolla, Rolla, MO, 1988. Tewari, A., "New Acceleration Potential Method for Supersonic Unsteady Aerodynamics of Lifting Surfaces, Further Extension of the Nonplanar Doublet Point Meth...

OBJECTIVE To determine whether echocardiographic markers thromboembolic risk differ between patients with pure atrial flutter and patients with atrial flutter and intermittent atrial fibrillation. DESIGN Patients with atrial flutter were followed up prospectively for 12 months to identify intermittent atrial fibrillation. After the follow up period, transthoracic and multiplane transoesophage...

Severe mode switching is often observed when the PK-method used in flutter analysis of complex aircraft configurations, particular nearly 100 vibrational modes are considered. In commonly commercial software NASTRAN, resulting eigenroots sorted an ascending order frequency. Therefore, appearance massive mode-switching instances cannot be avoided analyses, especially for engineering applications...

A model order reduction method is proposed for models of aeroservoelastic vehicles in the linear parameter-varying (LPV) systems framework, based on state space interpolation of modal forms. The dynamic order of such models is usually too large for control synthesis and implementation since they combine rigid body dynamics, structural dynamics and unsteady aerodynamics. Thus, model order reduct...

This paper investigates the coupled aeroelastic and flight dynamics stability of flexible lightweight aircraft. The aerodynamics are modelled by the discrete-time unsteady vortex lattice method, which can capture the large deformations of the lifting surfaces, and includes 3-D effects and in-plane motions. A geometrically-exact composite beam formulation is used to model the nonlinear flexible-...

An experimental model of a typical three degree-of-freedom airfoil section with composite control surface subjected to a two-dimensional, incompressible air-flow has been created. The flutter response of the system with both, a defect-free and with damaged control surfaces, were measured experimentally. An analytical model was implemented to predict the flutter response in the case of a defect-...

Background Slight variation in cycle lengths of common and rapid atrial flutter in humans is an established phenomenon, but its mechanisms have not been completely clarified. In a previous study, we demonstrated that in common atrial flutter the variations in atrial cycle length were due to atrial stretch affecting the revolution time of a reentrant circuit. In the present study, we investigate...