Energy spectra and bubble velocity distributions in pseudo-turbulence: Numerical simulations vs. experiments

Direct numerical simulations (DNS) are performed to study the behavior of a swarm of rising air bubbles in water, employing the front tracking method, which allows to handle finite-size bubbles. The swarms consist of monodisperse deformable 4 mm bubbles with a gas fraction of 5% and 15%. This paper focuses on the comparison of the liquid energy spectra and bubble velocity probability density functions (PDFs) with experimental data obtained by phase-sensitive constant-temperature anemometry (CTA) and three-dimensional particle tracking velocimetry (PTV), respectively.     

带税率的Cramér-Lundberg风险模型的总征税次数的分布函数(英文)

本文研究了带税率的Cramér-Lundberg风险模型.利用迭代算法及该过程具有的的强马氏性,得出了保险公司从开始营运到破产期间总赋税次数的概率函数.作为例子,本文给出了指数分布索赔假定下该概率函数的具体表达式.     

随机图的谱矩

简单图G的k阶谱矩定义为G的特征值的k阶幂之和,记为Mk(G).应用概率和代数的方法,对于几乎所有的图G,本文给出Mk(G)的一个精确估计.此外,对于几乎所有的多部图G,本文给出了Mk(G)的上界和下界.     

The Viro method for construction of Bernstein-Bézier algebraic hypersurface piece

This paper proposes a new method for the construction of Bernstein-Bézier algebraic hypersurface on a simplex with prescribed topology.The method is based on the combinatorial patchworking of Viro method.The topology of the Viro Bernstein-Bézier algebraic hypersurface piece is also described.     

Front velocity and directed polymers in random medium

We consider a stochastic model of N$N$ evolving particles studied by Brunet and Derrida. This model can be seen as a directed polymer in random medium with N$N$ sites in the transverse direction. Cook and Derrida use heuristic arguments to obtain a formula for the ground state energy of the polymer. We formalize their argument and show that there is an additional term in the formula in the critical case. We also consider a generalization of the model, and show that in the noncritical case the behavior is basically the same, whereas in the critical case a new correction appears.     

Real-time accurate Free-Form Deformation in terms of triangular Bézier surfaces

We implemented accurate FFD in terms of triangular Bézier surfaces as matrix multiplications in CUDA and rendered them via Open GL. Experimental results show that the proposed algorithm is more efficient than the previous GPU acceleration algorithm and tessellation shader algorithms.     

具有多个奇点的广义的Liénard系统不存在任何闭轨的条件

本文不同于一般的方法，利用辅助函数建立了具有多个奇点的广义的Ｌｉéｎａｒｄ系统（Ｅ）不存在任何闭轨的若干判别条件，关于（Ｅ）的经典的Ｂｅｎｄｉｘｓｏｎ判别法则和Ｐｏｉｎｃａｒé地形系法则是其特例．此外，给出了包括三次振动系统在内的例子．     

对于局部有界函数的积分型Szász-Bézier算子的逼近估计

引入一种积分型的 Szász- Bézier算子 ,并研究其逼近性质 ,得到了此类算子对局部有界函数的逼近阶估计公式     

Étude numérique de l'écoulement d'un fluide non newtonien thermodépendant entre deux plaques parallèles

In this study, the heat transfer of a non Newtonian thermodependent fluid flowing between two parallel plates is considered. The effects of different parameters on the evolutions of thermal boundary layer and of Nusselt number are numerically investigated in two heating cases and correlations are proposed to compute the heat transfer. To cite this article: N. Van Tuan, M. Lebouche, C. R. Mecanique 333 (2005).