flutter


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Related to flutter: atrial flutter, flutter device

flutter

1. Pathol an abnormally rapid beating of the auricles of the heart (200 to 400 beats per minute), esp in a regular rhythm, sometimes resulting in heart block
2. Electronics a slow variation in pitch in a sound-reproducing system, similar to wow but occurring at higher frequencies
3. Aeronautics a potentially dangerous oscillation of an aircraft, or part of an aircraft, caused by the interaction of aerodynamic forces, structural elastic reactions, and inertia
4. Music a method of sounding a wind instrument, esp the flute, with a rolling movement of the tongue

Flutter

 

in aeroelasticity, self-excited oscillations of parts of an aircraft, mainly the wing and the tail, that occur when the critical flutter speed is reached. Flutter may result in structural failure. Flutter is associated with the relative location of the center of gravity and the center of twist of the wing or tail and with other characteristics of a given aircraft.

flutter

[′fləd·ər]
(acoustics)
Distortion that occurs in sound reproduction as a result of undesired speed variations during the recording, duplicating, or reproducing process.
(electromagnetism)
A fast-changing variation in received signal strength, such as may be caused by antenna movements in a high wind or interaction with a signal or another frequency.
(engineering)
The irregular alternating motion of the parts of a relief valve due to the application of pressure where no contact is made between the valve disk and the seat.
(fluid mechanics)
(medicine)
Rapid, regular contraction of the atrial muscle of the heart.

Flutter (aeronautics)

An aeroelastic self-excited vibration with a sustained or divergent amplitude, which occurs when a structure is placed in a flow of sufficiently high velocity. Flutter is an instability that can be extremely violent. At low speeds, in the presence of an airstream, the vibration modes of an aircraft are stable; that is, if the aircraft is disturbed, the ensuing motion will be damped. At higher speeds, the effect of the airstream is to couple two or more vibration modes such that the vibrating structure will extract energy from the airstream. The coupled vibration modes will remain stable as long as the extracted energy is dissipated by the internal damping or friction of the structure. However, a critical speed is reached when the extracted energy equals the amount of energy that the structure is capable of dissipating, and a neutrally stable vibration will persist. This is called the flutter speed. At a higher speed, the vibration amplitude will diverge, and a structural failure will result. See Aeroelasticity

Aircraft manufacturers now have engineering departments whose primary responsibility is fluffer safety. Modern flutter analyses involve extensive computations, requiring the use of large-capacity, high-speed digital computers. Flutter engineers contribute to the design by recommending stiffness levels for the structural components and control surface actuation systems and weight distributions on the lifting surfaces, so that the aircraft vibration characteristics will not lead to flutter within the design speeds and altitudes. See Airframe, Wing

flutter

flutter
The wing twist as it flaps up and down. This up and down motion causes changes in the angle of attack. The changes in angle of attack mean that the aerodynamic forces are always tending to help the motion, which do not, therefore, damp out, resulting in flutter.
A vibration caused by the combined effects of the changes in pressure distribution over the surface of airfoils as the angle of attack is altered and the elastic forces set up by the distortion of the structure itself. In the worst cases, there may be a total loss of control and a consequent crash. The flutter may affect the control surfaces such as an aileron, or the main planes, or both. The flutter can be avoided by using mass balances, increasing structural rigidity, and having irreversible controls. Flutter also occurs with propellers, compressor blades, and turbine blades. Flutter is an aeroelastic self-excited vibration in which the external source of energy is the airstream. It depends on the elastic, inertial, and dissipative forces of the system in addition to the aerodynamic forces.
References in periodicals archive ?
For example, Flutter supports a so-called stateful Hot Reload feature that allows developers to experiment with their code, add features to it or fix bugs and almost immediately see the impact of those changes on the app.
If the inclination increases, the flutter critical speed decreases.
For more information about Amilia K Spicer, her Folk Alliance festival appearances, or for review copies of Fill Me Up and Wow and Flutter please contact: Chip Schutzman, Miles High Productions, chip@mileshighproductions.
The ultimate goal of flutter analysis is to calculate the structure of the bridge or flutter critical wind speed, in order to evaluate the flutter stability.
A lot of airplanes rely on correct cable tension as part of their flutter margin, although most of it is done by balancing the control surfaces.
Because the heart beats faster in atrial flutter, progress toward heart failure can occur faster than it can with afib.
3) Based on the well-known fact that internal and external damping can be transformed to Rayleigh damping, it is shown that the damping coefficients can be effectively determined using proportional damping and two damping coefficients can be reasonably estimated for real systems through a parametric study of damping coefficients in association with flutter loads of Beck's columns.
Well they did that, it lasted two weeks, then I went into flutter again.
Atrial flutter (AFL) is a common abnormal heart rhythm similar to atrial fibrillation (AF).
12 exclusive branded vans will facilitate women, in not only commuting between the twin cities, but also serve as a hub of information on ZonG Flutter packages with the added advantage of allowing women to avail recharge facility on the go.
Hollmann (1991) made a series of studies to predict critical flutter speeds of light aircraft structures.
He said that as many as 12 exclusive branded vans will facilitate women, in not only commuting between the twin cities, but also serve as a hub of information on Zong Flutter packages.