标题： 三维欧拉方程中的能量守恒在$\mathbb{T}^2\times \mathbb{R}_+$上 显示英文标题

标题： Energy conservation in the 3D Euler equations on $\mathbb{T}^2\times \mathbb{R}_+$

摘要： 本文的目的是在有边界域中证明不可压缩欧拉方程的能量守恒。我们研究的域是$\mathbb{T}^2\times\mathbb{R}_+$，其中边界既是平的又具有有限测度。然而，首先我们研究无边界域上的方程（整个空间$\mathbb{R}^3$，环面$\mathbb{T}^3$和混合空间$\mathbb{T}^2\times\mathbb{R}$）。 我们利用Duchon & Robert ({\it 非线性} {\bf 13} (2000) 249--255)的一些论点，在假设$u\in L^3(0,T;L^3(\mathbb{R}^3))$和其中一个积分条件\begin{equation*} \lim_{|y|\to 0}\frac{1}{|y|}\int^T_0\int_{\mathbb{R}^3} |u(x+y)-u(x)|^3\,d x\,d t=0 \end{equation*}或\begin{equation*} \int_0^T\int_{\mathbb{R}^3}\int_{\mathbb{R}^3}\frac{|u(x)-u(y)|^3}{|x-y|^{4+\delta}}\,d x\,d y<\infty,\qquad\delta>0, \end{equation*}的情况下证明能量守恒，其中第二个条件等价于要求对于某个$\alpha>1/3$，$u\in L^3(0,T;W^{\alpha,3}(\mathbb{R}^3))$。 我们然后利用这两个条件中的第一个来证明弱解$u$在$D_+:=\mathbb{T}^2\times \mathbb{R}_+$上的能量守恒：我们扩展$u$在整个$\mathbb{T}^2\times\mathbb{R}$上定义的解，然后在这个域上使用该条件来证明满足\begin{equation*} \lim_{|y|\to 0} \frac{1}{|y|}\int^{T}_{0}\iint_{\mathbb{T}^2}\int^\infty_{|y|}|u(t,x+y)-u(t,x)|^3 \,d x_3 \,d x_1 \,d x_2 \,d t=0, \end{equation*}和边界$\partial D_+=\{x_3=0\}$附近某些连续性条件的弱解$u\in L^3(0,T;L^3(D_+))$的能量守恒。 显示英文摘要

摘要： The aim of this paper is to prove energy conservation for the incompressible Euler equations in a domain with boundary. We work in the domain $\mathbb{T}^2\times\mathbb{R}_+$, where the boundary is both flat and has finite measure. However, first we study the equations on domains without boundary (the whole space $\mathbb{R}^3$, the torus $\mathbb{T}^3$, and the hybrid space $\mathbb{T}^2\times\mathbb{R}$). We make use of some of the arguments of Duchon \& Robert ({\it Nonlinearity} {\bf 13} (2000) 249--255) to prove energy conservation under the assumption that $u\in L^3(0,T;L^3(\mathbb{R}^3))$ and one of the two integral conditions \begin{equation*} \lim_{|y|\to 0}\frac{1}{|y|}\int^T_0\int_{\mathbb{R}^3} |u(x+y)-u(x)|^3\,d x\,d t=0 \end{equation*} or \begin{equation*} \int_0^T\int_{\mathbb{R}^3}\int_{\mathbb{R}^3}\frac{|u(x)-u(y)|^3}{|x-y|^{4+\delta}}\,d x\,d y<\infty,\qquad\delta>0, \end{equation*} the second of which is equivalent to requiring $u\in L^3(0,T;W^{\alpha,3}(\mathbb{R}^3))$ for some $\alpha>1/3$. We then use the first of these two conditions to prove energy conservation for a weak solution $u$ on $D_+:=\mathbb{T}^2\times \mathbb{R}_+$: we extend $u$ a solution defined on the whole of $\mathbb{T}^2\times\mathbb{R}$ and then use the condition on this domain to prove energy conservation for a weak solution $u\in L^3(0,T;L^3(D_+))$ that satisfies \begin{equation*} \lim_{|y|\to 0} \frac{1}{|y|}\int^{T}_{0}\iint_{\mathbb{T}^2}\int^\infty_{|y|}|u(t,x+y)-u(t,x)|^3 \,d x_3 \,d x_1 \,d x_2 \,d t=0, \end{equation*} and certain continuity conditions near the boundary $\partial D_+=\{x_3=0\}$.