arXiv subjects

Liutang Xue

Publications and source records attributed to Liutang Xue.

26 records · Page 2Linked to original sources

arXiv2018

Regularity results for a class of generalized surface quasi-geostrophic equations

We show a global existence result of weak solutions for a class of generalized Surface Quasi-Geostrophic equation in the inviscid case. We also prove the global regularity of such solutions for the equation with slightly supercritical dissipation, which turns out to correspond to a logarithmically supercritical diffusion due to the singular nature of the velocity. Our last result is the eventual regularity in the supercritical cases for such weak solutions. The main idea in the proof of the existence part is based on suitable commutator estimates along with a careful cutting into low/high frequencies and inner/outer spatial scales to pass to the limit; while the proof of both the global regularity result and the eventual regularity for the supercritical diffusion are essentially based on the use of the so-called modulus of continuity method.

math.AP↗

arXiv2016

On the Differentiability issue of the drift-diffusion equation with nonlocal Lévy-type diffusion

We investigate the differentiability issue of the drift-diffusion equation with nonlocal Lévy-type diffusion at either supercritical or critical type cases. Under the suitable conditions on the drift velocity and the forcing term in terms of the spatial Hölder regularity, we prove that the vanishing viscosity solution is differentiable with some Hölder continuous derivatives for any positive time.

math.AP↗

arXiv2015

Discretely self-similar singular solutions for the incompressible Euler equations

In this article we consider the discretely self-similar singular solutions of the Euler equations, and the possible velocity profiles concerned not only have decaying spatial asymptotics, but also have unconventional non-decaying asymptotics. By relying on the local energy inequality of the velocity profiles and the bootstrapping method, we prove some nonexistence results and show the energy behavior of the possible nontrivial velocity profiles. For the case with non-decaying asymptotics, the needed representation formula of the pressure profile in terms of velocity profiles is also given and justified.

math.AP↗

arXiv2015

On the locally self-similar singular solutions for the incompressible Euler equations

In this paper we consider the locally backward self-similar solutions for the Euler system, and focus on the case that the possible nontrivial velocity profiles have non-decaying asymptotics. We derive the meaningful representation formula of the pressure profile in terms of velocity profiles in this case, and by using it and the local energy inequality of profiles, we prove some nonexistence results and show the energy behavior concerning the possible velocity profiles.

math.AP↗

arXiv2012

On the well-posedness of a 2D nonlinear and nonlocal system arising from the dislocation dynamics

In this paper we consider a 2D nonlinear and nonlocal model describing the dynamics of the dislocation densities. We prove the local well-posedness of strong solution to this system in the suitable functional framework, and we show the global well-posedness for some dissipative cases by the method of nonlocal maximum principle.

math.AP↗

arXiv2011

Global Wellposedness for a Modified Critical Dissipative Quasi-Geostrophic Equation

In this paper we consider the following modified quasi-geostrophic equation \partial_{t}θ+u\cdot\nablaθ+ν|D|^αθ=0, \quad u=|D|^{α-1}\mathcal{R}^{\bot}θ,\quad x\in\mathbb{R}^2 with $ν>0$ and $α\in ]0,1[\,\cup \,]1,2[$. When $α\in]0,1[$, the equation was firstly introduced by Constantin, Iyer and Wu in \cite{ref ConstanIW}. Here, by using the modulus of continuity method, we prove the global well-posedness of the system with the smooth initial data. As a byproduct, we also show that for every $α\in ]0,2[$, the Lipschitz norm of the solution has a uniform exponential bound.

math.AP↗

arXiv2010

On the regularity of a class of generalized quasi-geostrophic equations

In this article we consider the following generalized quasi-geostrophic equation \partial_tθ+ u\cdot\nabla θ+ νΛ^βθ=0, \quad u= Λ^α\mathcal{R}^\botθ, \quad x\in\mathbb{R}^2, where $ν>0$, $Λ:=\sqrt{-Δ}$, $α\in ]0,1[$ and $β\in ]0,2[$. We first show a general criterion yielding the nonlocal maximum principles for the whole space active scalars, then mainly by applying the general criterion, for the case $α\in]0,1[$ and $β\in ]α+1,2]$ we obtain the global well-posedness of the system with smooth initial data; and for the case $α\in ]0,1[$ and $β\in ]2α,α+1]$ we prove the local smoothness and the eventual regularity of the weak solution of the system with appropriate initial data.

math.AP↗

arXiv2009

On the global well-posedness of a class of Boussinesq- Navier-Stokes systems

In this paper we consider the following 2D Boussinesq-Navier-Stokes systems \partial_{t}u+u\cdot\nabla u+\nabla p+ |D|^αu &= θe_{2} \partial_{t}θ+u\cdot\nabla θ+ |D|^βθ&=0 \quad with $\textrm{div} u=0$ and $0<β<α<1$. When $\frac{6-\sqrt{6}}{4}<α< 1$, $1-α<β\leq f(α) $, where $f(α)$ is an explicit function as a technical bound, we prove global well-posedness results for rough initial data.

math.AP↗