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arXiv 1901.05433math.APmath-phmath.MP
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具有表面张力的两种流体的Navier-斯托克斯方程的弱-强唯一性

Weak-strong uniqueness for the Navier-Stokes equation for two fluids with surface tension

Julian Fischer, Sebastian Hensel

摘要:

在目前的工作中,我们考虑的两种流体分离的尖锐的界面在表面张力的存在下,例如,在水中的油泡的演变。我们的主要结果是不可压Navier-Stokes方程斯托克斯方程相应自由边界问题的一个弱-强唯一性原理:只要存在一个强解,任何变倍解都必须与之重合。在没有物理奇点的情况下,变倍解的概念--其在时间上的整体存在性已由Abels [2]对一般的初始数据证明--不引入非唯一性机制。我们的方法的关键成分是一个相对熵功能的建设能够控制的接口错误。如果两种流体的粘度不一致,即使对于经典(强)解,速度场的梯度在界面处也会变得不连续,这就需要对相对熵进行仔细的额外调整。

英文摘要:

In the present work, we consider the evolution of two fluids separated by a sharp interface in the presence of surface tension - like, for example, the evolution of oil bubbles in water. Our main result is a weak-strong uniqueness principle for the corresponding free boundary problem for the incompressible Navier-Stokes equation: As long as a strong solution exists, any varifold solution must coincide with it. In particular, in the absence of physical singularities the concept of varifold solutions - whose global in time existence has been shown by Abels [2] for general initial data - does not introduce a mechanism for non-uniqueness. The key ingredient of our approach is the construction of a relative entropy functional capable of controlling the interface error. If the viscosities of the two fluids do not coincide, even for classical (strong) solutions the gradient of the velocity field becomes discontinuous at the interface, introducing the need for a careful additional adaption of the relative entropy.

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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