Journal of Fluid Mechanics

Focus on Fluids

Could waves mix the ocean?

G. FALKOVICHa1

a1 Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel

Abstract

A finite-amplitude propagating wave induces a drift in fluids. Understanding how drifts produced by many waves disperse pollutants has broad implications for geophysics and engineering. Previously, the effective diffusivity was calculated for a random set of small-amplitude surface and internal waves. Now, this is extended by Bühler & Holmes-Cerfon (J. Fluid Mech., 2009, this issue, vol. 638, pp. 5–26) to waves in a rotating shallow-water system in which the Coriolis force is accounted for, a necessary step towards oceanographic applications. It is shown that interactions of finite-amplitude waves affect particle velocity in subtle ways. An expression describing the particle diffusivity as a function of scale is derived, showing that the diffusivity can be substantially reduced by rotation.

Keywords

  • Waves;
  • drift;
  • diffusion;
  • nonlinearity
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