Separation of time-scales in drift-diffusion equations on ℝ2
File(s)1907.04012v1.pdf (691.2 KB)
Working paper
Author(s)
Zelati, MC
Dolce, M
Type
Working Paper
Abstract
We deal with the problem of separation of time-scales and filamentation in a linear drift-diffusion problem posed on the whole space $\mathbb{R}^2$. The passive scalar considered is stirred by an incompressible flow with radial symmetry. We identify a time-scale, much faster than the diffusive one, at which mixing happens along the streamlines, as a result of the interaction between transport and diffusion. This effect is also known as enhanced dissipation. For power-law circular flows, this time-scale only depends on the behavior of the flow at the origin. The proofs are based on an adaptation of a hypocoercivity scheme and yield a linear semigroup estimate in a suitable weighted $L^2$-based space.
Date Issued
2019-07-09
Publisher
arXiv
Copyright Statement
© 2019 The Author(s).
Identifier
http://arxiv.org/abs/1907.04012v1
http://arxiv.org/abs/1907.04012v1
Subjects
math.AP
math.AP
math.AP
math.AP
Notes
14 pages, 1 figure
Publication Status
Published