AskDefine | Define oscillation

Dictionary Definition

oscillation

Noun

1 the process of oscillating between states
2 (physics) a regular periodic variation in value about a mean [syn: vibration]
3 a single complete execution of a periodically repeated phenomenon; "a year constitutes a cycle of the seasons" [syn: cycle]

User Contributed Dictionary

English

Pronunciation

Noun

  1. the act of oscillating or the state of being oscillated
  2. a regular periodic fluctuation in value about some mean
  3. a single such cycle

Related terms

Translations

Extensive Definition

''For other uses, see oscillator (disambiguation)
Oscillation is the repetitive variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples include a swinging pendulum and AC power. The term vibration is sometimes used more narrowly to mean a mechanical oscillation but sometimes is used to be synonymous with "oscillation." Oscillations occur not only in physical systems but also in biological systems and in human society.

Simplicity

The simplest mechanical oscillating system is a mass attached to a linear spring, subject to no other forces; except for the point of equilibrium, this system is equivalent to the same one subject to a constant force such as gravity. Such a system may be approximated on an air table or ice surface. The system is in an equilibrium state when the spring is unstretched. If the system is displaced from the equilibrium, there is a net restoring force on the mass, tending to bring it back to equilibrium. However, in moving the mass back to the equilibrium position, it has acquired momentum which keeps it moving beyond that position, establishing a new restoring force in the opposite sense. The time taken for an oscillation to occur is often referred to as the oscillatory period.
The specific dynamics of this spring-mass system are described mathematically by the simple harmonic oscillator and the regular periodic motion is known as simple harmonic motion. In the spring-mass system, oscillations occur because, at the static equilibrium displacement, the mass has kinetic energy which is converted into potential energy stored in the spring at the extremes of its path. The spring-mass system illustrates some common features of oscillation, namely the existence of an equilibrium and the presence of a restoring force which grows stronger the further the system deviates from equilibrium.
The harmonic oscillator offers a model of many more complicated types of oscillation and can be extended by the use of Fourier analysis.

Damped, driven and self-induced oscillations

In real-world systems, the second law of thermodynamics dictates that there is some continual and inevitable conversion of energy into the thermal energy of the environment. Thus, damped oscillations tend to decay with time unless there is some net source of energy in the system. The simplest description of this decay process can be illustrated by the harmonic oscillator. In addition, an oscillating system may be subject to some external force (often sinusoidal), as when an AC circuit is connected to an outside power source. In this case the oscillation is said to be driven.
Some systems can be excited by energy transfer from the environment. This transfer typically occurs where systems are embedded in some fluid flow. For example, the phenomenon of flutter in aerodynamics occurs when an arbitrarily small displacement of an aircraft wing (from its equilibrium) results in an increase in the angle of attack of the wing on the air flow and a consequential increase in lift coefficient, leading to a still greater displacement. At sufficiently large displacements, the stiffness of the wing dominates to provide the restoring force that enables an oscillation.

Coupled oscillations

The harmonic oscillator and the systems it models have a single degree of freedom. More complicated systems have more degrees of freedom, for example two masses and three springs (each mass being attached to fixed points and to each other). In such cases, the behavior of each variable influences that of the others. This leads to a coupling of the oscillations of the individual degrees of freedom. For example, two pendulum clocks mounted on a common wall will tend to synchronise. The apparent motions of the individual oscillations typically appears very complicated but a more economic, computationally simpler and conceptually deeper description is given by resolving the motion into normal modes.

Continuous systems - waves

As the number of degrees of freedom becomes arbitrarily large, a system approaches continuity; examples include a string or the surface of a body of water. Such systems have (in the classical limit) an infinite number of normal modes and their oscillations occur in the form of waves that can characteristically propagate.

Examples

Optical

Economic and social

See also

External links

oscillation in Bosnian: Oscilovanje
oscillation in Catalan: Oscil·lació
oscillation in Czech: Kmitání
oscillation in Danish: Oscillator
oscillation in German: Schwingung
oscillation in Estonian: Võnkumine
oscillation in Modern Greek (1453-): Ταλάντωση
oscillation in Spanish: Oscilación
oscillation in Persian: نوسان
oscillation in French: Oscillation
oscillation in Korean: 진동
oscillation in Croatian: Titranje
oscillation in Ido: Ocilo
oscillation in Indonesian: Osilasi
oscillation in Italian: Oscillazione
oscillation in Hebrew: תנודה
oscillation in Latvian: Svārstības
oscillation in Malay (macrolanguage): Ayunan
oscillation in Dutch: Trilling
oscillation in Japanese: 振動 (物理現象)
oscillation in Norwegian: Oscillasjon
oscillation in Polish: Drgania
oscillation in Portuguese: Vibração
oscillation in Romanian: Oscilaţie
oscillation in Russian: Колебания
oscillation in Russian: Виброизоляция
oscillation in Simple English: Oscillator
oscillation in Slovak: Vibrácia
oscillation in Finnish: Oskillaattori
oscillation in Swedish: Oscillation
oscillation in Vietnamese: Dao động
oscillation in Ukrainian: Коливання
oscillation in Chinese: 振动

Synonyms, Antonyms and Related Words

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