Maximal turbulence as a selection criterion for measure-valued solutions

Fuente: arXiv
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Main Authors: Klingenberg, Christian, Markfelder, Simon, Wiedemann, Emil
Format: Preprint
Published: 2025
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author Klingenberg, Christian
Markfelder, Simon
Wiedemann, Emil
author_facet Klingenberg, Christian
Markfelder, Simon
Wiedemann, Emil
contents The quest for a good solution concept for the partial differential equations (PDEs) arising in mathematical fluid dynamics is an outstanding open problem. An important notion of solutions are the measure-valued solutions. It is well known that for many PDEs there exists a multitude of measure-valued solutions even if admissibility criteria like an energy inequality are imposed. Hence in recent years, people have tried to select the relevant solutions among all admissible measure-valued solutions or at least to rule out some solutions which are not relevant. In this paper another such criterion is studied. In particular, we aim to select generalized Young measures which are ``maximally turbulent''. To this end, we look for maximizers of a certain functional, namely the variance, or more precisely, the Jensen defect of the energy. We prove existence of such a maximizer and we show that its mean value and total energy is uniquely determined. Our theory is carried out in a very general setting which may be applied in many situations where maximally turbulent measures shall be selected among a set of generalized Young measures. Finally, we apply this general framework to the incompressible and the isentropic compressible Euler equation. Our criterion of maximal turbulence is plausible and leads to existence and uniqueness in a certain sense (in particular, the mean value and the total energy of different maximally turbulent solutions coincide).
format Preprint
id arxiv_https___arxiv_org_abs_2503_20343
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Maximal turbulence as a selection criterion for measure-valued solutions
Klingenberg, Christian
Markfelder, Simon
Wiedemann, Emil
Analysis of PDEs
35D99, 76M30 (primary), 35Q31, 76B03, 76N10, 76F99 (secondary)
The quest for a good solution concept for the partial differential equations (PDEs) arising in mathematical fluid dynamics is an outstanding open problem. An important notion of solutions are the measure-valued solutions. It is well known that for many PDEs there exists a multitude of measure-valued solutions even if admissibility criteria like an energy inequality are imposed. Hence in recent years, people have tried to select the relevant solutions among all admissible measure-valued solutions or at least to rule out some solutions which are not relevant. In this paper another such criterion is studied. In particular, we aim to select generalized Young measures which are ``maximally turbulent''. To this end, we look for maximizers of a certain functional, namely the variance, or more precisely, the Jensen defect of the energy. We prove existence of such a maximizer and we show that its mean value and total energy is uniquely determined. Our theory is carried out in a very general setting which may be applied in many situations where maximally turbulent measures shall be selected among a set of generalized Young measures. Finally, we apply this general framework to the incompressible and the isentropic compressible Euler equation. Our criterion of maximal turbulence is plausible and leads to existence and uniqueness in a certain sense (in particular, the mean value and the total energy of different maximally turbulent solutions coincide).
title Maximal turbulence as a selection criterion for measure-valued solutions
topic Analysis of PDEs
35D99, 76M30 (primary), 35Q31, 76B03, 76N10, 76F99 (secondary)
url https://arxiv.org/abs/2503.20343