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论文中文题名:

 三维非线性阻尼微极流方程解的一些渐近性质研究    

姓名:

 谢晓甜    

学号:

 20201103006    

保密级别:

 公开    

论文语种:

 chi    

学科代码:

 0701    

学科名称:

 理学 - 数学    

学生类型:

 硕士    

学位级别:

 理学硕士    

学位年度:

 2023    

培养单位:

 西安科技大学    

院系:

 理学院    

专业:

 数学    

研究方向:

 偏微分方程及其应用    

第一导师姓名:

 宋雪丽    

第一导师单位:

 西安科技大学    

论文提交日期:

 2023-06-14    

论文答辩日期:

 2023-06-01    

论文外文题名:

 Study of some asymptotic properties of the solution of the three-dimensional nonlinear damping micropolar flow equation    

论文中文关键词:

 微极流方程 ; 一致估计 ; 一致吸引子 ; 连续依赖性    

论文外文关键词:

 Micropolar flow equation ; Uniform estimations ; Uniform attractor ; Continuous dependencies    

论文中文摘要:

微极流方程描述了一类包含微旋转效应和惯性力的非牛顿流体运动,能较好地表征一些经典的Navier-Stokes模型无法描述的不可压缩流体动力学行为. 近年来,微极流方程的理论研究成为偏微分方程领域的热点内容,本文将对三维微极流方程解的渐近性态,尤其是解的一致吸引子的存在性进行讨论,并探讨解对部分系数的连续依赖性问题. 主要研究内容如下:
研究了具有非线性阻尼项的三维微极流方程一致吸引子的存在性. 首先,当参数3<β<5,初值(uττ)∈V1xV2和外力(f1,f2)∈ℋ(f10)xℋ(f20) 时,对方程解进行一系列一致估计证明了过程{U(f1,f2)(t,τ)}t≥τ在空间((V1xV2)x(ℋ(f10)xℋ(f20)),V1xV2)是连续的,并应用过程理论得到(V1xV2 ,V1xV2)一致吸引子的存在性. 进一步证明了过程{U(f1,f2)(t,τ)}t≥τ 是(V1xV2,2(Ω)x2(Ω))一致紧的. 并因此得到 (V1xV2,2(Ω)x2(Ω))一致吸引子的存在性,最后运用反证法证明了(V1xV2 ,V1xV2)一致吸引子实际上是(V1xV2,2(Ω)x2(Ω))的一致吸引子.
讨论了三维非线性阻尼微极流方程解对部分系数的连续依赖性. 首先利用一致吸引子中对方程解的一致估计. 其次,借助先验估计,运用三线性不等式、Gagliardo-Nirenberg不等式和Gronwall不等式获得方程解的差的范数所满足的微分不等式. 最终得到微极流方程的解关于初值及系数ν,κ,γ的连续依赖性结论.

论文外文摘要:

The micropolar flow equations describe the motion of a class of non-Newtonian fluids containing micro-rotational effects and inertial forces, and can better characterize the dynamical behavior of some incompressible fluids that cannot be described by the classical Navier-Stokes model. The mathematical theory of this model has been a hot research topic in the field of partial differential equations in recent decades. In this paper, we will discuss the asymptotic states of the solutions of the three-dimensional micropolar flow equation with nonlinear damping, especially the existence of uniform attractors of the solutions, and explore the continuous dependence of the solutions on some coefficients. The main research contents are as follows.

We study the existence of uniform attractors for 3D micropolar equation with nonlinear damping term. When3<β<5  , initial data(uττ)∈V1xV2  and the external forces (f1,f2)∈ℋ(f10)xℋ(f20) , we give a series of uniform estimates on the solutions. According to these estimates, we prove the family of processes {U(f1,f2)(t,τ)}t≥τ is((V1xV2)x(ℋ(f10)xℋ(f20)),V1xV2)  -continuous. Meanwhile, we find that {U(f1,f2)(t,τ)}t≥τ is (V1xV2,2(Ω)x2(Ω)) -uniformly compact. Finally, we obtain the existence of (V1xV2,2(Ω)x2(Ω)) -uniform attractor and (V1xV2,2(Ω)x2(Ω)) -uniform attractor. And we prove the (V1xV2 ,V1xV2) -uniform attractor is actually the (V1xV2,2(Ω)x2(Ω)) -uniform attractor.

We discuss the continuous dependence of the solutions of the three-dimensional micropolar flow equations with nonlinear damping on some coefficients. Firstly, by the uniform estimation of the solution of the equation in the uniform attractor. Secondly, with the help of these estimates, the differential inequality satisfied by the norm of the difference in the solution of the equation is obtained by using the trilinear inequality, Gagliardo-Nirenber inequality and the Gronwall inequality. Finally, by solving the differential inequality, the continuous dependence of the solution of the micropolar flow equation on initial values and coefficients  ν,κ,γ  is obtained.

中图分类号:

 O175.2    

开放日期:

 2023-06-14    

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