Material Barriers to Diffusive and Stochastic Transport
Abstract
We seek transport barriers and transport enhancers as material surfaces across which the transport of diffusive tracers is minimal or maximal in a general, unsteady flow. We find that such surfaces are extremizers of a universal, non-dimensional transport functional whose leading-order term in the diffusivity can be computed directly from the flow velocity. The most observable (uniform) transport extremizers are explicitly computable as null-surfaces of an objective transport tensor. Even in the limit of vanishing diffusivity, these surfaces differ from all previously identified coherent structures for purely advective fluid transport. Our results extend directly to stochastic velocity fields and hence enable transport barrier and enhancer detection under uncertainties.
Cite
@article{arxiv.1808.04787,
title = {Material Barriers to Diffusive and Stochastic Transport},
author = {George Haller and Daniel Karrasch and Florian Kogelbauer},
journal= {arXiv preprint arXiv:1808.04787},
year = {2019}
}
Comments
Accepted, non-copyedited version (Proceedings of the National Academy of Sciences)