in this study, nonlocal nonlinear instability and the vibration of a double carbon nanotube (cnt) system have been investigated. the visco-pasternak model is used to simulate the elastic medium between nanotubes, on which the effect of the spring, shear and damping of the elastic medium is considered. both of the cnts convey a viscose fluid and a uniform longitudinal magnetic field is applied t...

The identification of nonlinear aeroelastic systems based on the Volterra theory of nonlinear systems is presented. Recent applications of the theory to problems in experimental aeroelasticity are reviewed. These results include the identification of aerodynamic impulse responses, the application of higher-order spectra (HOS) to wind-tunnel flutter data, and the identification of nonlinear aero...

The Benchmark Active Controls Technology (BACT) project is part of NASA Langley Research Center’s Benchmark Models Program for studying transonic aeroelastic phenomena. In January of 1996 the BACT wind-tunnel model was used to successfully demonstrate the application of robust multivariable control design methods (H∞ and μ-synthesis) to flutter suppression. This paper addresses the design and e...

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...

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-...

It is not generally believed that there is a relation between atrial flutter, thought to be due to a single reentrant circuit, and atrial fibrillation, thought to be due to simultaneously circulating multiple-reentrant wave fronts. However, there are many reasons to suggest that these rhythms are more closely related than previously thought. To test the hypothesis that the length of an area of ...

In this paper, we investigate unsteady behavior of flexible vessels carrying a blood flow. Membrane model with constant tension for the vessel walls and incompressible newtonian fluid approximation for blood is adopted. Developed computational model is applied to simulate the coupled fluid-wall behavior in 2D collapsible channels and 3D collapsible tubes. INTRODUCTION Vessels carrying blood flo...

ENSAERO [1], is a multidisciplinary code for computing the unsteady flow and associated aeroelastic responses of aerospace vehicles. The code simultaneously integrates the time-dependent Euler or thin-layer, Reynolds-averaged Navier-Stokes equations and the structural equations of motion using aeroelastically adaptive dynamic grids. The code can predict static and dynamic response for flexible ...

AIMS To determine the diagnostic information contained in cardiac pulsatile pressure waves as expressed in the Doppler signals recorded over the right lung. METHODS AND RESULTS The pulsatile characteristics of the pulmonary vascular system were studied by means of the novel pulse Doppler technology in 38 control volunteers, 31 patients with atrial fibrillation (AF) and 7 patients with atrial ...