Non-uniqueness of Admissible Solutions for the 2D Euler Equation with Vortex Data

F Mengual - Communications in Mathematical Physics, 2024 - Springer
For any 2< p<∞ we prove that there exists an initial velocity field v∘∈ L 2 with vorticity ω∘∈
L 1∩ L p for which there are infinitely many bounded admissible solutions v∈ C t L 2 to the …

Dissipative Euler flows originating from circular vortex filaments

F Gancedo, A Hidalgo-Torné, F Mengual - arXiv preprint arXiv:2404.04250, 2024 - arxiv.org
In this paper, we prove the first existence result of weak solutions to the 3D Euler equation
with initial vorticity concentrated in a circle and velocity field in $ C ([0, T], L^{2^-}) $. The …

Entropy solutions to macroscopic IPM

Á Castro, D Faraco, B Gebhard - arXiv preprint arXiv:2309.03637, 2023 - arxiv.org
We investigate maximal potential energy dissipation as a selection criterion for subsolutions
(coarse grained solutions) in the setting of the unstable Muskat problem. We show that both …

Rigorous results on conserved and dissipated quantities in ideal MHD turbulence

D Faraco, S Lindberg, L Székelyhidi - Geophysical & Astrophysical …, 2022 - Taylor & Francis
We review recent mathematical results on the theory of ideal MHD turbulence. On the one
hand, we explain a mathematical version of Taylor's conjecture on magnetic helicity …

Mixing solutions for the Muskat problem with variable speed

F Noisette, L Székelyhidi - Journal of Evolution Equations, 2021 - Springer
We provide a quick proof of the existence of mixing weak solutions for the Muskat problem
with variable mixing speed. Our proof is considerably shorter and extends previous results in …

Localized mixing zone for Muskat bubbles and turned interfaces

Á Castro, D Faraco, F Mengual - Annals of PDE, 2022 - Springer
We construct mixing solutions to the incompressible porous media equation starting from
Muskat type data in the partially unstable regime. In particular, we consider bubble and …

On a degenerate elliptic problem arising in the least action principle for Rayleigh–Taylor subsolutions

B Gebhard, J Hirsch, JJ Kolumbán - Annales de l'Institut Henri Poincaré …, 2024 - ems.press
We address a degenerate elliptic variational problem arising in the application of the least
action principle to averaged solutions of the inhomogeneous Euler equations in the …

On bounded two-dimensional globally dissipative Euler flows

B Gebhard, JJ Kolumbán - SIAM Journal on Mathematical Analysis, 2022 - SIAM
We examine the two-dimensional Euler equations including the local energy (in) equality as
a differential inclusion and show that the associated relaxation essentially reduces to the …

On the energy-constrained optimal mixing problem for one-dimensional initial configurations

B Gebhard - arXiv preprint arXiv:2409.16886, 2024 - arxiv.org
We consider the problem of mixing a passive scalar in a periodic box by incompressible
vector fields subject to a fixed energy constraint. In that setting a lower bound for the time in …

[HTML][HTML] Plasma Waves and Rayleigh–Taylor Instability: Theory and Application

S Singh, B Vidhani, S Yogi, A Tyagi… - Plasma Science …, 2023 - intechopen.com
The presence of plasma density gradient is one of the main sources of Rayleigh–Taylor
instability (RTI). The Rayleigh–Taylor instability has application in meteorology to explain …