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101.
Giuseppe Cardone Sergey A. Nazarov Jan Sokolowski Jari Taskinen 《Comptes Rendus Mecanique》2007,335(12):763-767
We construct the asymptotics (as ε→0) of solutions to the Neumann problem for the Laplace equation and of the corresponding Dirichlet integral. The problem concerns a three-dimensional domain having two connected components of the boundary at the distance ε>0. To cite this article: G. Cardone et al., C. R. Mecanique 335 (2007). 相似文献
102.
A two-phase model based upon principles of continuum mixture theory is numerically solved to predict the evolution of detonation
in a granulated reactive material. Shock to detonation transition (SDT) is considered whereby combustion is initiated due
to compression of the material by a moving piston. In particular, this study demonstrates the existence of a SDT event which
gives rise to a steady two-phase Chapman-Jouguet (CJ) detonation structure consisting of a single lead shock in the gas and
an unshocked solid; this structure has previously been independently predicted by a steady-state theory. The unsteady model
equations, which constitute a non-strictly hyperbolic system, are numerically solved using a modern high-resolution method.
The numerical method is based on Godunov's method, and utilizes an approximate solution for the two-phase Riemann problem.
Comparisons are made between numerical predictions and known theoretical results for 1) an inert two-phase shock tube problem,
2) an inert compaction wave structure, and 3) a reactive two-phase detonation structure; in all cases, good agreement exists.
Received 4 August 1995 / Accepted 17 February 1996 相似文献
103.
We investigate the behavior of fluid–particle mixtures subject to shear stress, by mean of direct simulation. This approach is meant to give some hints to explain the influence of interacting red cells on the global behavior of the blood. We concentrate on the apparent viscosity, which we define as a macroscopic quantity which characterizes the resistance of a mixture against externally imposed shear motion. Our main purpose is to explain the non-monotonous variations of this apparent viscosity when a mixture of fluid and interacting particles is submitted to shear stress during a certain time interval. Our analysis of these variations is based on preliminary theoretical remarks, and some computations for some well-chosen static configurations. To cite this article: A. Lefebvre, B. Maury, C. R. Mecanique 333 (2005). 相似文献
104.
落锤试验中炸药样品表面能的多重分形性质 总被引:1,自引:0,他引:1
从能量守恒和质量守恒出发结合炸药样品在受冲击压缩时的分形性质,证明在样品周边的表面能具有多重分形的结构。 相似文献
105.
106.
In this Note we present an approach to determine the local minima of a specific class of minimization problems. Attention is focused on the inextensibility condition of flexible rods expressed as a nonconvex constraint. Two algorithms are derived from a special splitting of the Lagrangian into the difference of two convex functions (DC). They are compared to the augmented Lagrangian methods used in this context. These DC formulations are easily extended to contact problems and applied to the determination of confined buckling shapes. To cite this article: P. Alart, S. Pagano, C. R. Mecanique 330 (2002) 819–824. 相似文献
107.
Results of eigenvalue analysis based on global and local eigenvalue considerations are presented. A collocation method with
the Chebyshev polynomial approximation has been used for the global eigenvalue analysis. The results explain the appearance
of a second unstable mode. In the case of real frequencies with Reynolds number R < 381 there is only one unstable mode. This mode coalesces at R≈ 381 with a stable mode. At R > 381 they become separated by interchannging their branches, then the second unstable mode occurs. The receptivity problem
has been considered with respect to perturbations emanating from a wall. The results illustrate that high-frequency modes
have a stronger response than low-frequency modes. It is shown that the method of expansion in a biorthogonal eigenfunction
system and the method used by Ashpis and Reshotko are equivalent with regard to the receptivity problem solution.
Received: 29 March 1996 and accepted 26 November 1996 相似文献
108.
Detonation propagation behavior associated with sudden expansions has been investigated both experimentally and numerically.
Different mechanisms, from sustained propagation to detonation failure and reinitiation including shock and flame front decoupling
and recoupling have been observed with the schlieren technique. The shock-induced flame propagation has been modeled with
two-step chemistry and structured two-dimensional CFD on arbitrary geometries. The results of the numerical simulations show
good correspondence to the variety of phenomena observed in experiments. Thus the numerical simulation can be used to study
detonation propagation in complex geometries. It provides a tool for the design of safety devices and aids experimental investigations.
Received 4 August 1995 / Accepted 25 April 1996 相似文献
109.
The paper provides some results concerning the numerical study of the strongly transient gasdynamic processes in a pressure-wave
refrigerator (PWR). A hierarchical set of numerical models from the simplest one-dimensional to a fully three-dimensional
formulation is introduced. The computations show that one-dimensional solutions give a reasonable foundation for the understanding
of PWR operational principles but cannot satisfactorily predict the refrigeration efficiency. Good agreement with experiment
is achieved by considering two- and three-dimensional effects of gas mixing by overlap of rotating nozzles and expansion tubes.
Received
Received 14 February 1996 / Accepted 1 June 1996 相似文献
110.
Claude Valle Jean-Marie Souriau Gry de Saxc Danielle Fortun 《Comptes Rendus Mecanique》2004,332(12):1013-1018
We show that the affine structure of the 3-dimensional space is deeply enmeshed with the static laws expression. The relevance of tensorial rules for calculus in mechanics is thus enhanced. The virtual work principle is stated precisely but a little twist is given to the usual statements: the tensorial nature of the so-called virtual displacement vector is asserted to be covariant. To cite this article: C. Vallée et al., C. R. Mecanique 332 (2004).