the effect of axial deformation of shell particles on the dynamic instability (flutter) of cantilevered cylindrical shells made of functionally graded materials (fgm) under an end axial follower force is addressed. to this end, at first, results for free vibration of fgm cylindrical shells were verified with previous outcomes and they were in very good agreement. then, the effect of axial defor...

The goal of the flutter shutter is to make uniform motion blur invertible, by a “fluttering” shutter that opens and closes on a sequence of well chosen sub-intervals of the exposure time interval. In other words, the photon flux is modulated according to a well chosen sequence called flutter shutter code. This article provides a numerical method that computes optimal flutter shutter codes in te...

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...

Background. We report that rapid atrial pacing interrupts atrial flutter when the orthodromic wave front from the pacing impulse is blocked in an area of slow conduction in the reentry circuit. To characterize the area of slow conduction during atrial flutter and rapid pacing, we studied 11 episodes of induced atrial flutter, mean cycle length 157+±20 msec, in eight dogs with sterile pericardit...

The prediction of flutter instability is of major concern for design of flexible structures. This necessitates the identification of aeroelastic parameters, known as flutter derivatives from wind tunnel experiments. The extraction of flutter derivatives becomes more challenging when the number of degrees of freedom (DOF) increases from two to three. Since the work in the field of identifying al...

Ocular flutter is an eye movement disorder characterized by purely horizontal rapid saccadic oscillations lasting for a few minutes which stops spontaneously. Postinfectious ocular flutter and truncal ataxia are a rare entity. There are reported cases of opsoclonus myoclonus ataxia in association with dengue virus infection. However, there are no reported cases of parainfectious ocular flutter ...

Tonal, non-vocal sounds are widespread in both ordinary bird flight and communication displays. We hypothesized these sounds are attributable to an aerodynamic mechanism intrinsic to flight feathers: aeroelastic flutter. Individual wing and tail feathers from 35 taxa (from 13 families) that produce tonal flight sounds were tested in a wind tunnel. In the wind tunnel, all of these feathers could...

Feathers can produce sound by fluttering in airflow. This flutter is hypothesized to be aeroelastic, arising from the coupling of aerodynamic forces to one or more of the feather's intrinsic structural resonance frequencies. We investigated how mode of flutter varied among a sample of hummingbird tail feathers tested in a wind tunnel. Feather vibration was measured directly at ~100 points acros...

Unsteady helicopter rotor aerodynamics are complicated. This paper reviews some of the fundamentals and newer developments of unsteady helicopter aerodynamics. Rotor flow is beautiful and complex. Visualizing rotor flow allows for an appreciation of the following theories and solution attempts as well as nature’s complexities. The flow through a helicopter rotor with forward motion is shown in ...

In this study the centre manifold is applied for reduction and limit cycle calculation of a highly nonlinear structural aeroelastic wing. The limit cycle is arisen from structural nonlinearity due to the large deflection of the wing. Results obtained by different orders of centre manifolds are compared with those obtained by time marching method (fourth-order Runge-Kutta method). These comparis...