共查询到20条相似文献,搜索用时 15 毫秒
1.
Mirosław Lachowicz 《Nonlinear dynamics》1994,5(3):393-399
A finite system of stochastic interacting particles is considered. The system approximates the solutions of the kinetic equations (the Boltzmann equation, the Boltzmann-Enskog equation) as well as the solutions describing the macroscopic evolution of fluids: the Euler and the Navier-Stokes hydrodynamic equations. 相似文献
2.
Some conclusions about the smooth function classes stability for the basic system of equations of atmospheric motion and instability for Navier-Stokes equation are summarized. On the basis of this, by taking the basic system of equations of atmospheric motion via Boussinesq approximation as example to explain in detail that the instability about some simplified models of the basic system of equations for atmospheric motion is caused by the instability of Navier-Stokes equation, thereby, a principle to guarantee the stability of simplified equation is drawn in simplifying the basic system of equations. 相似文献
3.
凹坑表面活塞与缸套挤压润滑油的流固耦合数值模拟 总被引:2,自引:0,他引:2
在准油膜润滑条件下,采用Coupling Euler Lagrange(CEL)方法对凹坑表面活塞-缸套挤压润滑油过程进行了流固耦合数值模拟.润滑油动力学方程由Euler坐标系下的Navier-Stokes(N-S)方程来描述,活塞-缸套采用Lagrange坐标系下的线弹性力学方程来描述.罚函数约束方法将Lagrange结构的物理量传递给润滑油流体单元,实现流体和固体的直接耦合.仿真结果表明:CEL模型较好地追踪了挤压过程中润滑油的自由液面;凹坑表面裙部将润滑油挤压到贮油凹坑中,而光滑裙部只有挤压过程,无法贮存润滑油;随着润滑油的逐渐排出,接触应力逐渐增大,光滑裙部的接触应力增大尤为明显;凹坑中贮存的润滑油承载比稳定在0.3,该油膜具有一定的承载能力.数值模拟结果和试验数据的变化趋势吻合. 相似文献
4.
Thomas J. R. Hughes 《国际流体数值方法杂志》1987,7(11):1261-1275
SUPG methods were originally developed for the scalar advection-diffusion equation and the incompressible Navier-Stokes equations. In the last few years successful extensions have been made to symmetric advective-diffusive systems and, in particular, the compressible Euler and Navier-Stokes equations. New procedures have been introduced to improve resolution of discontinuities and thin layers. In this paper a brief overview is presented of recent progress in the development and understanding of SUPG methods. 相似文献
5.
Tai-Ping Liu Tong Yang Shih-Hsien Yu Hui-Jiang Zhao 《Archive for Rational Mechanics and Analysis》2006,181(2):333-371
It is well known that the Boltzmann equation is related to the Euler and Navier-Stokes equations in the field of gas dynamics.
The relation is either for small Knudsen number, or, for dissipative waves in the time-asymptotic sense. In this paper, we
show that rarefaction waves for the Boltzmann equation are time-asymptotic stable and tend to the rarefaction waves for the
Euler and Navier-Stokes equations. Our main tool is the combination of techniques for viscous conservation laws and the energy
method based on micro-macro decomposition of the Boltzmann equation. The expansion nature of the rarefaction waves and the
suitable microscopic version of the H-theorem are essential elements of our analysis. 相似文献
6.
MICROCOSMIC BOUND THEOREM OF DAYCY'S LAW AND ITS APPLICATION 总被引:1,自引:0,他引:1
By combining Chapman-Enskog expansion with the BGK approximation to Baltzmann equation and Navier-Stokes equation was obtained. And an expression of Darcy‘ s law was obtained through taking variable average over Navier-Stokes equation on some representative space in porous media, and finally an example was taken to prove its reliability. 相似文献
7.
8.
We consider here the problem of deriving rigorously from Boltzmann's equation, globally in time and for general initial conditions, fluid mechanics equations such as the Navier-Stokes or Euler equations. 相似文献
9.
By the aid of an idea of the weighted ENO schemes, some weight-type high-resolution difference schemes with different orders
of accuracy are presented in this paper by using suitable weights instead of the minmod functions appearing in various TVD
schemes. Numerical comparisons between the weighted schemes and the non-weighted schemes have been done for scalar equation,
one-dimensional Euler equations, two-dimensional Navier-Stokes equations and parabolized Navier-Stokes equations.
The project supported by the National Natural Science Foundation of China (19582007) and Partly by State Key Laboratory of
Scientific/Engineering Computing. 相似文献
10.
By combining Chapman-Enskog expansion with the BGK approximation to Baltzmann equation and Navier-Stokes equation was obtained.
And an expression of Darcy’s law was obtained through taking variable average over Navier-Stokes equation on some representative
space in porous media, and finally an example was taken to prove its reliability.
Foundation items: the National Natural Science Foundation of China (10372094); the Natural Science Foundation of Zhejiang Province, China
(M103082, M102053); the Science Foundation of Education Department of Zhejiang Province, China (20030871)
Biography: Xu You-sheng (1963∼), Associate Professor, Doctor 相似文献
11.
Shi Wei-hui 《应用数学和力学(英文版)》1994,15(12):1125-1130
In this paper, the necessary conditions of the existence of C2 solutions in some initial problems of Navier-Stokes equations are given, and examples of instability of initial value (at
t=0) problems are also given. The initial value problem of Navier-Stokes equation is one of the most fundamental problem for
this equation various authors studies this problem and contributed a number of results. J. Lerav, a French professor, proved
the existence of Navier-Stokes equation under certain defined initial and boundary value conditions. In this paper, with certain
rigorously defined key concepts, based upon the basic theory of J. Hadamard partial differential equations1, gives a fundamental theory of instability of Navier-Stokes equations. Finally, many examples are given, proofs referring
to Ref. [4]. 相似文献
12.
STABILITYOFNAVIER-STOKESEQUATION(II)ShiWei-hui(施惟慧);FangXiao-zuo(方晓佐)(ShanghaiUniversity),Shanghai(ReceivedDec.11,1993;Commun... 相似文献
13.
14.
Random attractors 总被引:7,自引:0,他引:7
Hans Crauel Arnaud Debussche Franco Flandoli 《Journal of Dynamics and Differential Equations》1997,9(2):307-341
In this paper, we generalize the notion of an attractor for the stochastic dynamical system introduced in [7]. We prove that the stochastic attractor satisfies most of the properties satisfied by the usual attractor in the theory of deterministic dynamical systems. We also show that our results apply to the stochastic Navier-Stokes equation, the white noise-driven Burgers equation, and a nonlinear stochastic wave equation. 相似文献
15.
针对一种充气前缘(inflatable leading edge, ILE)增升技术,建立了其充气结构与流场耦合作用的运动方程. 将方程写成状态空间形式,采用时域推进方法求解. 对使用了变前缘增升技术的NACA63-212翼型进行了充气结构静变形的数值计算,结果表明充气结构的刚度对翼型的气动特性有明显影响. 与原翼型相比,在不考虑充气结构变形时, 该增升技术大约能使翼型的失速迎角增加30{\%},最大升力系数增加22{\%};考虑结构变形后增升效果有所降低. 刚度较低的薄膜在前缘吸力峰的作用下会隆起形成鼓包,容易引起流动分离. 相似文献
16.
著名的理想流体定常流动的能量方程即伯努利方程,自建立以来在流体力学领域中贡献卓著。本文依据伯努利方程的建立内涵,阐述了其在流体静力学、定常孔口出流、皮托管测速、文丘里管流量和翼型绕流等具体流动中的成功应用。同时,进一步说明了由伯努利方程建立提出的局部跟随流体质点的建模思想,被欧拉概括为描述流体运动的流场法,是建立欧拉方程组和N-S方程组的基本依据,也为后来湍流理论、边界层理论、气动噪声等理论的建立奠定了基础。 相似文献
17.
Patrick J. Roache 《国际流体数值方法杂志》1988,8(11):1459-1463
This work comments on a recent paper by J. C. Strikwerda in SIAM Journal on Scientific and Statistical Computing, in an attempt to clear up the evident confusion regarding the use of a Poisson equation for pressure in incompressible Navier-Stokes solutions. 相似文献
18.
Applying the theory of stratification, the solution space structure about a class of deformed Navier-Stokes equation isdetermined.
It is proved that such kind of equation has no Ck (k≥2) stable solution by the fact that the strate transversale is a null set.
Foundation item: the National Natural Science Foundation of China (19971054), Shanghai Natural Science Foundation (99ZA14034)
Biography: HE You-hua (1960-) 相似文献
19.
Shi Wei-hui 《应用数学和力学(英文版)》1994,15(9):865-866
In this paper we give an example of non-uniqueness of local solution for some kinds of boundary value problem of Navier-Stokes
equation. 相似文献
20.
不可压粘流N-S方程的边界积分解法 总被引:1,自引:0,他引:1
对原变量的N-S方程进行一阶时间离散,采用共轭梯度法解除压强-速度的耦合.对所得的一系列Laplace方程、Possion方程和Helmhotz方程均进行边界积分法求解,首次得到了粘性N-S方程的边界积分表示式.圆柱的定常、非定常尾迹计算结果表明了本文方法的有效性. 相似文献