In numerous fields of study, the component of instability within a system is generally characterized by some of the outputs or internal states growing without bounds. Not all systems that are not stable are unstable; systems can also be marginally stable or exhibit limit cycle behavior.
In control theory, a system is unstable if any of the roots of its characteristic equation has real part greater than zero (or if zero is a repeated root). This is equivalent to any of the eigenvalues of the state matrix having either real part greater than zero, or, for the eigenvalues on the imaginary axis, the algebraic multiplicity being larger than the geometric multiplicity.
In structural engineering, a structure can become unstable when excessive load is applied. Beyond a certain threshold, structural deflections magnify stresses, which in turn increases deflections. This can take the form of buckling or crippling. The general field of study is called structural stability.
Atmospheric instability is a major component of all weather systems on Earth.
Other articles related to "instability":
... After the instability has run its course, the system is typically "hotter" (the motions are more random) or rounder than before ... Instabilities in stellar systems include Bar instability of rapidly-rotating disks Jeans instability Firehose instability Gravothermal instability Radial-orbit instability Various instabilities in cold rotating ...
... In order for a boundary layer to be absolutely unstable (have an inviscid instability), it must satisfy Rayleigh's criterion namely Where represents the y-derivative and is the free stream velocity ... that viscosity must be an important factor in the instability ... is the Reynolds stress term and is the primary production method for instability growth ...
... The Omani invasion began a period of political instability and a quick succession of outside rulers took power with consequent destruction ... The years of almost constant warfare and instability in the period led to a demographic collapse – German geographer Carsten Niebuhr found in 1763 that Bahrain's 360 towns and ...
... higher dimensions are found to exhibit an instability to small perturbations ... It is very interesting to know the end point of this instability, particularly whether it leads to a phase transition forming a black hole ... a critical dimension has been found to exist below which the end state of instability is a black hole phase, i.e ...
... Instability Field Person(s) Named After Bénard instability Natural convection, Rayleigh–Bénard convection Henri Bénard Benjamin–Feir instability Surface gravity waves T ... Feir Buneman instability Plasma physics Oscar Buneman Cherenkov instability Plasma physics Pavel Alekseevič Čerenkov Chromo-Weibel instability Plasma ... Weibel Crow instability Aerodynamics S ...
Famous quotes containing the word instability:
“With one more talent one frequently stands with greater instability than with one less, as a table stands better on three legs than on four.”
—Friedrich Nietzsche (18441900)
“The difference between tragedy and comedy is the difference between experience and intuition. In the experience we strive against every condition of our animal life: against death, against the frustration of ambition, against the instability of human love. In the intuition we trust the arduous eccentricities were born to, and see the oddness of a creature who has never got acclimatized to being created.”
—Christopher Fry (b. 1907)
“What exacerbates the strain in the working class is the absence of money to pay for services they need, economic insecurity, poor daycare, and lack of dignity and boredom in each partners job. What exacerbates it in upper-middle class is the instability of paid help and the enormous demands of the career system in which both partners become willing believers. But the tug between traditional and egalitarian models of marriage runs from top to bottom of the class ladder.”
—Arlie Hochschild (20th century)