High rayleigh number convection with gaseous helium at low temperature

1996 ◽  
Vol 104 (1-2) ◽  
pp. 109-129 ◽  
Author(s):  
X. Chavanne ◽  
F. Chill� ◽  
B. Chabaud ◽  
B. Castaing ◽  
J. Chaussy ◽  
...  
Keyword(s):  
Rayleigh Number ◽  
Low Temperature ◽  
Gaseous Helium

High Rayleigh Number Convection with Gaseous Helium at Low Temperature

1996 ◽  
pp. 213-214
Author(s):  
X. Chavanne ◽  
F. Chillà ◽  
B. Chabaud ◽  
B. Castaing ◽  
J. Chaussy ◽  
...  
Keyword(s):  
Rayleigh Number ◽  
Low Temperature ◽  
Gaseous Helium

Intermittency in a turbulent low temperature gaseous helium jet

2000 ◽  
Vol 17 (2) ◽  
pp. 309-317 ◽  
Author(s):  
O. Chanal ◽  
B. Chabaud ◽  
B. Castaing ◽  
B. Hébral
Keyword(s):  
Low Temperature ◽  
Gaseous Helium ◽  
Helium Jet

scholarly journals The low temperature properties of gaseous helium, Errata

1938 ◽  
Vol 169 (937) ◽  
pp. 205-205 ◽  
Keyword(s):  
Low Temperature ◽  
Perturbation Method ◽  
Gaseous Helium ◽  
The Difference

Equation (7) should read: “ V( r ) = 10 -9 e - r /0·217 — 1·91 x 10 -12 r -6 ergs, being 1·30 times that given by Slater. This function, which necessarily has a zero in the same position as Slater’s function, provides a suitable startingpoint from which to determine the exact interaction, as there is evidence that Slater’s function gives too small a repulsion at small distances and too small an attraction at intermediate distances.” This modification affects the discussion in the last paragraph of §3. The differences between the results of this paper and those of Massey and Mohr using the Slater interaction are probably largely due to the difference in magnitude of the interactions employed but may be partly due also to the inaccuracy of the perturbation method employed by Massey and Mohr to obtain the smaller positive phases. The discussion of §3 then applies.

Properties of low-temperature ytterbium condensates grown in a medium of gaseous helium

2003 ◽  
Vol 29 (11) ◽  
pp. 928-933 ◽  
Author(s):  
V. M. Kuz’menko ◽  
A. N. Vladychkin
Keyword(s):  
Low Temperature ◽  
Gaseous Helium

scholarly journals Superconducting instrumentation for high Reynolds turbulence experiments with low temperature gaseous helium

2003 ◽  
Vol 386 ◽  
pp. 512-516 ◽  
Author(s):  
S. Pietropinto ◽  
C. Poulain ◽  
C. Baudet ◽  
B. Castaing ◽  
B. Chabaud ◽  
...  
Keyword(s):  
Low Temperature ◽  
Gaseous Helium ◽  
High Reynolds

Influence of transverse magnetic field on breakdown characteristics of vacuum, gaseous helium at low temperature and liquid helium

Cryogenics ◽  
1989 ◽  
Vol 29 (4) ◽  
pp. 448-456 ◽  
Author(s):  
M. Hara ◽  
H. Shigematsu ◽  
S. Yano ◽  
K. Yamafuji ◽  
M. Takeo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Low Temperature ◽  
Liquid Helium ◽  
Transverse Magnetic Field ◽  
Transverse Magnetic ◽  
Gaseous Helium

Free convection in low-temperature gaseous helium

1975 ◽  
Vol 67 (1) ◽  
pp. 17-28 ◽  
Author(s):  
D. C. Threlfall
Keyword(s):  
Rayleigh Number ◽  
Free Convection ◽  
Room Temperature ◽  
Critical Rayleigh Number ◽  
High Sensitivity ◽  
Temperature Fluctuations ◽  
Gaseous Helium ◽  
Short Time ◽  
Improved Accuracy ◽  
Very High

Free convection has been studied in gaseous helium at low temperatures in a cylindrical vessel of aspect ratio (diameterlheight) 2·5. Compared with measurements in fluids at room temperature the present arrangement has the advantages of small size, a short time constant and improved accuracy. As the Rayleigh number was varied from 60 to 2 × 109, the Nusselt number rose from 1 to 69, obeying the relationNu= 0·173Ra0·2800±0·0005over the upper four decades ofRa.The critical Rayleigh number was 1630, but the conditions of the experiment did not allow reliable measurements at such low values ofRa.The very high sensitivity within a given experiment showed the presence of several ‘discrete transitions’, which were often step like and not merely a change of gradient as reported by other workers. The largest of these, atRa= 3 · 105, involved a drop in heat flux of some 6% and was somewhat hysteretic. The temperature fluctuations increased markedly as the step was crossed.

Thermal convection with gaseous helium at low temperature

1996 ◽  
Vol 46 (S1) ◽  
pp. 91-92
Author(s):  
Xavier Chavanne ◽  
Francesca Chillà ◽  
Benoît Chabaud ◽  
Bernard Castaing ◽  
Jacques Chaussy ◽  
...  
Keyword(s):  
Low Temperature ◽  
Thermal Convection ◽  
Gaseous Helium

Effect of Wall Thermal Boundary Conditions on the Development of Three-Dimensional, Unsteady Natural Convective Flow in a Horizontal Enclosure With a Heated Strip on the Lower Surface

2004 ◽  
Author(s):  
Patrick H. Oosthuizen ◽  
Jane T. Paul
Keyword(s):  
Boundary Condition ◽  
Rayleigh Number ◽  
Low Temperature ◽  
Cross Section ◽  
Three Dimensional ◽  
Lower Surface ◽  
Vertical Side ◽  
Thermal Boundary Conditions ◽  
Side Walls ◽  
Rayleigh Numbers

Flow in a rectangular enclosure with a square vertical cross-section normal to the longitudinal coordinate direction and having a strip on the lower horizontal surface which is heated to a uniform high temperature has been numerically studied. Two wall thermal boundary conditions have been considered. In one, the longitudinal vertical side walls are cooled to a uniform low temperature and the horizontal top surface is adiabatic while in the other the longitudinal vertical side walls and the horizontal top surface are cooled to a uniform low temperature. In both cases, the square vertical end walls of the enclosure are adiabatic. It has been assumed that the flow is laminar and that the fluid properties are constant except for the density change with temperature which gives rise to the buoyancy forces. The unsteady, three-dimensional governing equations, expressed in dimensionless form, have been solved using a finite-difference procedure. The solution was started with no flow in the enclosure. The solution, in general, has the following parameters: the Rayleigh Number, Ra, the Prandtl number, Pr, the dimensionless longitudinal length of the enclosure relative to the size of the square cross-section, Ay, the dimensionless width of the heated strip on the lower surface relative to the size of the square cross-section, wH, and the thermal boundary condition on the upper surface. Results have only been obtained for a Prandtl number of 0.7 and only results for wH = 1/3 will be presented. Results have been obtained for values of Ay between 0.5 and 2 for Rayleigh numbers up to 5×105. In all cases, three-dimensional unsteady flow has been found to exist at the higher Rayleigh numbers. The conditions under which this unsteady flow develops and the effect of Ay on the variation of the mean Nusselt number with Rayleigh number and the effect of the wall surface boundary condition on these results has been investigated.

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