We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Enhanced Dissipation, Hypoellipticity, and Anomalous Small Noise Inviscid Limits in Shear Flows.
- Authors
Bedrossian, Jacob; Coti Zelati, Michele
- Abstract
We analyze the decay and instant regularization properties of the evolution semigroups generated by two-dimensional drift-diffusion equations in which the scalar is advected by a shear flow and dissipated by full or partial diffusion. We consider both the space-periodic $${\mathbb{T}^2}$$ setting and the case of a bounded channel $${\mathbb{T} \times [0,1]}$$ with no-flux boundary conditions. In the infinite Péclet number limit (diffusivity $${\nu\to 0}$$ ), our work quantifies the enhanced dissipation effect due to the shear. We also obtain hypoelliptic regularization, showing that solutions are instantly Gevrey regular even with only partial diffusion. The proofs rely on localized spectral gap inequalities and ideas from hypocoercivity with an augmented energy functional with weights replaced by pseudo-differential operators (of a rather simple form). As an application, we study small noise inviscid limits of invariant measures of stochastic perturbations of passive scalars, and show that the classical Freidlin scaling between noise and diffusion can be modified. In particular, although statistically stationary solutions blow up in $${H^1}$$ in the limit $${\nu \to 0}$$ , we show that viscous invariant measures still converge to a unique inviscid measure.
- Subjects
ENERGY dissipation; SHEAR flow; HYPOELLIPTIC differential equations; INVISCID flow; HEAT equation; GEVREY class
- Publication
Archive for Rational Mechanics & Analysis, 2017, Vol 224, Issue 3, p1161
- ISSN
0003-9527
- Publication type
Article
- DOI
10.1007/s00205-017-1099-y