- Journal Article
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, nondimensional 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. Show more
Journal / seriesProceedings of the National Academy of Sciences of the United States of America
Pages / Article No.
PublisherNational Academy of Sciences
SubjectDiffusive Transport; Stochastic transport; Turbulence; Coherent structures; Variation calculus
Organisational unit03973 - Haller, George / Haller, George
MoreShow all metadata