Abstract
In 1921 G. I. Taylor introduced (with little discussion) the
notion that the dispersion
of a conserved passive scalar in a turbulent flow is determined by the
motion of fluid
particles (independent of the molecular diffusivity). Here, a hypothesis
of diffusivity
independence is introduced, which provides a sufficient condition for the
validity
of Taylor's approach. The hypothesis, which is supported by DNS data,
is that,
at high Reynolds number, the mean of the scalar conditional on the velocity
is
independent of the molecular diffusivity. From this hypothesis it is shown
that (at
high Reynolds number) the conditional Laplacian of the scalar is zero.
This new
result has several significant implications for models of turbulent mixing,
and for
the scalar flux. Primarily, a model of turbulent scalar mixing that is
independent of
velocity is inconsistent with the hypothesis, and gives rise to a spurious
source or
(more likely) sink of the scalar flux.
Publisher
Cambridge University Press (CUP)
Subject
Mechanical Engineering,Mechanics of Materials,Condensed Matter Physics
Cited by
79 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献