page_title: Instability
section_title: Fluid instabilities
hierarchical_section_title: Instability / Fluid instabilities
caption_attribution_description: English: This image, taken using a Nikon D40X with a 105mm lens and a Xenon flash lamp with ~1us duration, shows an unstable flow structure generated from the collision of two impinging jets with the diameter of 0.85mm.
context_page_description: 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 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.
context_section_description: Fluid instabilities occur in liquids, gases and plasmas, and are often characterized by the shape that form; they are studied in fluid dynamics and magnetohydrodynamics. Fluid instabilities include:
  Ballooning mode instability (some analogy to the Rayleigh–Taylor instability); found in the magnetosphere
  Atmospheric instability
  Hydrodynamic instability or dynamic instability (atmospheric dynamics)
  Inertial instability; baroclinic instability; symmetric instability, conditional symmetric or convective symmetric instability; barotropic instability; Helmholtz or shearing instability; rotational instability
  Hydrostatic instability or static instability/vertical instability (parcel instability), thermodynamic instability (atmospheric thermodynamics)
  Conditional or static instability, buoyant instability, latent instability, nonlocal static instability, conditional-symmetric instability; convective, potential, or thermal instability, convective instability of the first and second kind; absolute or mechanical instability
  Bénard instability
  Drift mirror instability
  Kelvin–Helmholtz instability (similar, but different from the diocotron instability in plasmas)
  Rayleigh–Taylor instability
  Plateau-Rayleigh instability (similar to the Rayleigh–Taylor instability)
  Richtmyer-Meshkov instability (similar to the Rayleigh–Taylor instability)
  Shock Wave Instability
  Benjamin-Feir Instability (also known as modulational instability)
caption: Unstable flow structure generated from the collision of two impinging jets.
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