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arXiv physics/0203070physics.flu-dyn
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二维不可压缩理想小障碍物绕流

Two dimensional incompressible ideal flow around a small obstacle

D. Iftimie, M. C. Lopes Filho, H. J. Nussenzveig Lopes

摘要:

本文研究了当障碍物很小时,在单个光滑障碍物外的不可压缩、理想、时间相关的二维流动的渐近行为。我们的主要目的是确定的方程所满足的极限流量。我们将看到,渐近行为取决于$γ$,即障碍物周围的环流。对于绕单个障碍物的光滑流,$γ$是由初始数据确定的守恒量。我们将证明,如果$γ= 0$,极限流满足标准的不可压缩欧拉方程在全平面内,但如果$γ\neq 0$,极限方程获得一个额外的强迫项。我们对待这个问题,首先构建一个序列的近似解的不可压缩的2D欧拉方程在全平面的精确解时,解决方程的外部的每个障碍,然后通过限制弱制定的方程。我们使用显式处理的格林函数的外部域的基础上共形映射,{ \it先验}估计通过仔细检查的限制过程和Div-Curl引理,连同一个标准的弱收敛处理的非线性通道的限制。

英文摘要:

In this article we study the asymptotic behavior of incompressible, ideal, time-dependent two dimensional flow in the exterior of a single smooth obstacle when the size of the obstacle becomes very small. Our main purpose is to identify the equation satisfied by the limit flow. We will see that the asymptotic behavior depends on $γ$, the circulation around the obstacle. For smooth flow around a single obstacle, $γ$ is a conserved quantity which is determined by the initial data. We will show that if $γ= 0$, the limit flow satisfies the standard incompressible Euler equations in the full plane but, if $γ\neq 0$, the limit equation acquires an additional forcing term. We treat this problem by first constructing a sequence of approximate solutions to the incompressible 2D Euler equation in the full plane from the exact solutions obtained when solving the equation on the exterior of each obstacle and then passing to the limit on the weak formulation of the equation. We use an explicit treatment of the Green's function of the exterior domain based on conformal maps, {\it a priori} estimates obtained by carefully examining the limiting process and the Div-Curl Lemma, together with a standard weak convergence treatment of the nonlinearity for the passage to the limit.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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