Küppers-Lortz instability

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The Küppers-Lortz instability or the Küppers-Lortz chaos (named after Günter Küppers and Dietrich Lortz ) is a phenomenon from fluid mechanics .

If a layer of liquid is heated from below and cooled from above, the static layer becomes unstable above a certain amount of the temperature gradient and a steady convection flow sets in. Depending on the temperature difference between the top and the bottom, it can take on different patterns - from a simple rolling flow to a honeycomb-shaped hexagonal flow. In this case, the liquid flows up in the center of the honeycomb and down at the edges.

If the liquid layer rotates around an axis perpendicular to the layer, the classic patterns of convection flow above a critical value of the rotational speed become unstable even with the smallest temperature differences - the patterns change over time. These changes do not happen locally as a constant transition from one pattern to another, rather the change happens globally and suddenly. This phenomenon is called Küppers-Lortz chaos or instability in the literature. It plays a role in brain research in explaining spontaneous changes in perception in tilted figures , e.g. B. Necker's cube.

literature

  • G. Küppers: The stability of steady finite amplitude convection in a rotating fluid layer . In: Physics Letters A . tape 32 , no. 1 , June 1970, p. 7-8 , doi : 10.1016 / 0375-9601 (70) 90052-6 .
  • G. Küppers, D. Lortz: Transition from Laminar Convection to Thermal Turbulence in a Rotating Fluid Layer . In: Journal of Fluid Mechanics . tape 35 , no. 03 , 1969, p. 609-620 , doi : 10.1017 / S0022112069001327 .
  • WVR Malkus, G. Veronis: Finite Amplitude Cellular Convection . In: Journal of Fluid Mechanics . tape 4 , no. 03 , 1958, p. 225-260 , doi : 10.1017 / S0022112058000410 .
  • A. Schlueter, D. Lortz, F. Busse: On the Stability of Steady Finite Amplitude Convection . In: Journal of Fluid Mechanics . tape 23 , no. 1 , 1965, p. 129-144 , doi : 10.1017 / S0022112065001271 .