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Existence and Non-Uniqueness of Ergodic Leray-Hopf Solutions to the Stochastic Power-Law Flows

Stefanie Elisabeth Berkemeier

TL;DR

This work addresses the existence and non-uniqueness of Leray–Hopf solutions for stochastic power-law flows with shear-thinning behavior in dimensions $d\ge 3$, where the power-law index satisfies $\iota\in\left(1, \frac{2d}{d+2}\right)$. It develops a stochastic convex integration framework augmented by a novel auxiliary energy functional to enforce the energy inequality and achieve global-in-time control, yielding infinitely many probabilistically strong Leray–Hopf solutions and, via Krylov–Bogoliubov and Krein–Milman, infinitely many ergodic stationary solutions. The paper extends the non-uniqueness paradigm to stochastic non-Newtonian fluids in this intermediate index range, providing regularity, energy estimates, and ergodic properties for the constructed solutions. The results significantly advance understanding of long-time behavior, ergodicity, and energy dissipation for stochastic shear-thinning flows and open avenues for further exploration of ergodic theory in non-Newtonian SPDEs.

Abstract

We study long time behavior of shear-thinning fluid flows in $d \geq 3$ dimensions, driven by additive stochastic forcing of trace class, with power-law indices ranging from $1$ to $ \frac{2d}{d+2}$. We particularly focus on Leray-Hopf solutions, i.e. on analytically weak solutions satisfying energy inequality. Introducing a new kind of energy related functional into the technique of convex integration enables the construction of infinitely many such solutions that are probabilistically strong for a certain initial value. Furthermore, we provide global i time estimates which lead to the existence of infinitely many stationary and even ergodic Leray--Hopf solutions. These results represent the first construction of Leray-Hopf solutions in the framework of stochastic shear-thinning fluids within this range of power-law indices.

Existence and Non-Uniqueness of Ergodic Leray-Hopf Solutions to the Stochastic Power-Law Flows

TL;DR

This work addresses the existence and non-uniqueness of Leray–Hopf solutions for stochastic power-law flows with shear-thinning behavior in dimensions , where the power-law index satisfies . It develops a stochastic convex integration framework augmented by a novel auxiliary energy functional to enforce the energy inequality and achieve global-in-time control, yielding infinitely many probabilistically strong Leray–Hopf solutions and, via Krylov–Bogoliubov and Krein–Milman, infinitely many ergodic stationary solutions. The paper extends the non-uniqueness paradigm to stochastic non-Newtonian fluids in this intermediate index range, providing regularity, energy estimates, and ergodic properties for the constructed solutions. The results significantly advance understanding of long-time behavior, ergodicity, and energy dissipation for stochastic shear-thinning flows and open avenues for further exploration of ergodic theory in non-Newtonian SPDEs.

Abstract

We study long time behavior of shear-thinning fluid flows in dimensions, driven by additive stochastic forcing of trace class, with power-law indices ranging from to . We particularly focus on Leray-Hopf solutions, i.e. on analytically weak solutions satisfying energy inequality. Introducing a new kind of energy related functional into the technique of convex integration enables the construction of infinitely many such solutions that are probabilistically strong for a certain initial value. Furthermore, we provide global i time estimates which lead to the existence of infinitely many stationary and even ergodic Leray--Hopf solutions. These results represent the first construction of Leray-Hopf solutions in the framework of stochastic shear-thinning fluids within this range of power-law indices.

Paper Structure

This paper contains 54 sections, 18 theorems, 236 equations, 2 figures, 4 tables.

Key Result

Theorem 1.7

For a certain initial value, $\iota\in(1,\frac{2d}{d+2})$ and sufficiently small $\gamma \in (0,1)$ there exist infinitely many ergodic Leray--Hopf solutions to PLF, which belong $\mathcal{P}$-a.s. to the class

Figures (2)

  • Figure 1: Relationships among the components of the next iteration step $v_{q+1}$.
  • Figure 2: Construction of the diagonal sequence $\left( d_n\right)_{n \in \mathbb{N}}$, which consists of the elements in the pink boxes.

Theorems & Definitions (41)

  • Definition 1.1
  • Definition 1.2
  • Remark 1.3
  • Definition 1.4
  • Definition 1.5
  • Definition 1.6
  • Theorem 1.7
  • Lemma 2.1
  • Lemma 2.2
  • Lemma 2.3
  • ...and 31 more