Fickian diffusion by random simple waves

Abstract

      Fickian diffusion caused by velocity fluctuations that can be described as a stochastic wave is examined. It is demonstrated, if some asumptions on stochastic variables of Eulerian velocity and particle displacement hold, that only waves with phase velocity less than standard deviations of velocity fluctuations can produce the Fickian diffusion. The result is disscused on the examples of horizontal mixing in the sea.