Presse et revues
80 pages
- Aller à la page de la table des matièresI
- SOMMAIRE/SUMMARY
- .......... Page(s) .......... III
- .......... Page(s) .......... 77
- Mécanique analytique/Analytical Mechanics
- Mécanique des solides et des structures/Mechanics of Solids and Structure
- Mécanique des fluide/Fluid Mechanics
- Instabilité et turbulence/Instability and Turbulence
- (voir tome 323, série II b, 1996, p. 95 see Tome 323, Series II b, 1996, p. 95)
- Mécanique des fluides numérique/Computational Fluid Mechanics
- .......... Page(s) .......... 112
- Physique statistique, thermodynamique/Statisticalphysicsh physics, thermodynamics
- .......... Page(s) .......... 113
- Relativité, gravitation/Relativity, gravitation
- .......... Page(s) .......... 126
- Chimie métallurgique/Metallurgic chemistry
- .......... Page(s) .......... 127
- Chronique de la Chimie/History of chemistry
- .......... Page(s) .......... 133
- CONTENTS
- .......... Page(s) .......... 79
- .......... Page(s) .......... 79
- We consider the movement of a material point in the plane, under a force which derives from a given potential, in polar coordinate, by
. The normal variational equation in the neighbourhood of the straight-line solution y = 0 is: - (1) ,
- where verifies the equation:
- (2) .
- We give the solutions for,and for any value of by using the Liouville transformation.
- We also study the singular points of the solution(t).
- .......... Page(s) .......... 87
- A high-speed train entering a tunnel generates a strong pressure jump which propagates inside the tunnel. This paper presents investigations on the formation of the compression wave generated by the entering of the train nose: experimentally, with a scale-model facility, tests have been undertaken from 0 to 30 m/s with different lengths of train nose and differents hapes of entry portals; numerically, a one-dimensional unsteady compressible flow calculation method based on the method of characteristics has been developed and compared to experimental results.
- We study with the aid of direct-numerical simulations the influence of a solid-body rotation of spanwise axis upon turbulence in a channel. Rotation is shown to reduce the vortical activity in the cyclonic zone. In the anticyclonic region, hairpin vortices are reorganized by rotation, and become more and more coherent and inclined towards the wall as the rotation rate increases. One observes also in this region the formation of a constant mean-velocity gradient equal to the entrainment vorticity and, if the rotation rate is high enough, the disappearance of high and low-speed streaks at the wall.
- Instability and Turbulence
- Influence of a solid-body rotation upon coherent vortices in a channel, Éric LAMB ALLAIS, Marcel LESIEUR and Olivier MÉTAIS (see Tome 323, Series II b, 1996, p. 95)
- .......... Page(s) .......... 113
- .......... Page(s) .......... 113
- We discuss the possibility of a new low-temperature instability of vortex tubes to a "folded" state, driven by the coupling to the normal electron states inside the cores. The basic mechanism is that a bent tube creates an effective potential for the electrons, which destabilizes the tube in a way reminiscent of the usual Peierls instability.
- .......... Page(s) .......... 127
- In this report we present the influence of various heteroatomic systems on the anti-wear and extreme-pressure properties of organo-sulfur compounds. Following mechanical testing on a four-ball machine and corrosion tests, it was shown that certain functions (especially thiocyanates) have interesting properties whereas those containing one or several oxygen atoms give poor performances.
- COMPTES RENDUS DE L'ACADÉMIE DES SCIENCES
- .......... Page(s) .......... III-V
- .......... Page(s) .......... III-V
- Mécanique analytique
- .......... Page(s) .......... 79
- Mécanique des solides et des structures
- .......... Page(s) .......... 83
- Mécanique des fluides
- Instabilité et turbulence
- (voir tome 323, série II b, 1996, p. 95)
- Mécanique des fluides numérique
- .......... Page(s) .......... 103
- Physique statistique, thermodynamique
- .......... Page(s) .......... 113
- Relativité, gravitation
- High frequency gravitational waves and interaction with matterYvonne CHOQUET-BRUHATand Antonio GRECO.......... Page(s) .......... 117
- Chimie métallurgique
- Chronique de la Chimie
- .......... Page(s) .......... 133
Le taux de reconnaissance estimé pour ce document est de 99.96%.
En savoir plus sur l'OCR
En savoir plus sur l'OCR
Le texte affiché peut comporter un certain nombre d'erreurs. En effet, le mode texte de ce document a été généré de façon automatique par un programme de reconnaissance optique de caractères (OCR). Le taux de reconnaissance estimé pour ce document est de 99.96%.
Facebook
Twitter
Pinterest