Everything about Oscillate totally explained
» 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's 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's some continual and inevitable conversion of energy into the
thermal energy of the environment. Thus,
damped oscillations tend to decay with time unless there's 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
See also:
list of wave topics
Mechanical
Electrical
Alternating current
Armstrong oscillator
Astable multivibrator
Blocking oscillator
Clapp oscillator
Colpitts oscillator
Delay line oscillator
Electronic oscillator
Hartley oscillator
Oscillistor
Pierce oscillator
Relaxation oscillator
RLC circuit
Royer oscillator
Vačkář oscillator
Wien bridge oscillator
Oscillators and Multivibrators
Virtual Cathode Oscillator
Electro-mechanical
Crystal oscillator
Loudspeaker
Microphone
Optical
Laser (oscillation of electromagnetic field with frequency of order Hz in the transient regime)
Quantum oscillator may refer to an optical local oscillator, as well as to a usual model in quantum optics.
Biological
Circadian rhythm
Prey-predator systems
Neural oscillations
Human
Brain waves
Pilot-induced oscillation
Voice production
Insulin release oscillations
Economic and social
Business cycle
Generation gap
Malthusian economics
News cycle
Climate and geophysics
Chandler wobble
El Niño-Southern Oscillation
Quasi-biennial oscillation
Tides in the Earth's oceans
Chemical
Belousov-Zhabotinsky reaction
Mercury beating heartFurther Information
Get more info on 'Oscillate'.
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