Critical velocities for superfluid-helium flow through a small hole

1974 ◽  
Vol 9 (2) ◽  
pp. 885-892 ◽  
Author(s):  
J. P. Hulin ◽  
D. D'Humieres ◽  
B. Perrin ◽  
A. Libchaber
Keyword(s):  
Superfluid Helium ◽  
Small Hole ◽  
Helium Flow ◽  
Flow Through ◽  
Critical Velocities

Superfluid helium flow through porous media

Cryogenics ◽  
1996 ◽  
Vol 36 (9) ◽  
pp. 667-673 ◽  
Author(s):  
H. Nakai ◽  
N. Kimura ◽  
M. Murakami ◽  
T. Haruyama ◽  
A. Yamamoto
Keyword(s):  
Porous Media ◽  
Superfluid Helium ◽  
Flow Through Porous Media ◽  
Helium Flow ◽  
Flow Through

Superfluid Helium Flow Through an Orifice Near Critical Velocity

1967 ◽  
Vol 19 (15) ◽  
pp. 822-824 ◽  
Author(s):  
W. J. Trela ◽  
W. M. Fairbank
Keyword(s):  
Critical Velocity ◽  
Superfluid Helium ◽  
Helium Flow ◽  
Flow Through

Transition to Turbulent State of Superfluid Helium Flow through Thermomechanical Pump Element

1996 ◽  
pp. 273-280 ◽  
Author(s):  
Hirotaka Nakai ◽  
Nobuhiro Kimura ◽  
Masahide Murakami ◽  
Tomiyoshi Haruyama ◽  
Akira Yamamoto
Keyword(s):  
Superfluid Helium ◽  
Helium Flow ◽  
Flow Through

scholarly journals Superfluid Helium Flow through Porous Media.

1996 ◽  
Vol 31 (9) ◽  
pp. 474-480
Author(s):  
Hirotaka NAKAI ◽  
Nobuhiro KIMURA ◽  
Masahide MURAKAMI ◽  
Tomiyoshi HARUYAMA ◽  
Akira YAMAMOTO
Keyword(s):  
Porous Media ◽  
Superfluid Helium ◽  
Flow Through Porous Media ◽  
Helium Flow ◽  
Flow Through

Effect of Surface Roughness on Gaseous Flow Through Microchannels

2000 ◽  
Author(s):  
Stephen E. Turner ◽  
Hongwei Sun ◽  
Mohammad Faghri ◽  
Otto J. Gregory
Keyword(s):  
Surface Roughness ◽  
Reynolds Number ◽  
Friction Factor ◽  
Reynolds Numbers ◽  
Helium Flow ◽  
Local Pressure ◽  
Aspect Ratios ◽  
Corrugated Surfaces ◽  
Flow Through ◽  
Effect Of Surface

Abstract This paper presents an experimental investigation on nitrogen and helium flow through microchannels etched in silicon with hydraulic diameters between 10 and 40 microns, and Reynolds numbers ranging from 0.3 to 600. The objectives of this research are (1) to fabricate microchannels with uniform surface roughness and local pressure measurement; (2) to determine the friction factor within the locally fully developed region of the microchannel; and (3) to evaluate the effect of surface roughness on momentum transfer by comparison with smooth microchannels. The friction factor results are presented as the product of friction factor and Reynolds number plotted against Reynolds number. The following conclusions have been reached in the present investigation: (1) microchannels with uniform corrugated surfaces can be fabricated using standard photolithographic processes; and (2) surface features with low aspect ratios of height to width have little effect on the friction factor for laminar flow in microchannels.

Upscaling of superfluid helium flow in porous media

2010 ◽  
Vol 53 (21-22) ◽  
pp. 4852-4864 ◽  
Author(s):  
H. Allain ◽  
M. Quintard ◽  
M. Prat ◽  
B. Baudouy
Keyword(s):  
Porous Media ◽  
Superfluid Helium ◽  
Flow In Porous Media ◽  
Helium Flow

On the Effects of Water Discharge Through Radial Gates at the Caruachi Dam

2010 ◽  
Author(s):  
Douglas Sanchez ◽  
Juan E. Salazar
Keyword(s):  
Water Flow ◽  
Water Discharge ◽  
Three Dimensional ◽  
Flow Induced Vibration ◽  
Discharge Flow ◽  
Cfd Models ◽  
Flow Through ◽  
Critical Velocities ◽  
Flow Effects

This paper presents numerical simulation of the water flow through the radial gates of the 2,280 MW Caruchi Dam, in southern Venezuela, and its relation to the vibration of the dam’s spillways and adjacent Control Building. The study is conducted as a contribution in determining the source of vibration of the fore mentioned structures in the case of gates opening above the normal values of up to 5 m, which occur when a larger water discharge is required in order to maintain an adequate level of the reservoir during the rainy season. The aim of the study was to find the pressure distribution and velocity profiles of the discharge flow through one of the dam’s radial gates and determine critical (reduced) velocities that may result in flow-induced vibration of the gates, as they were deemed to be the source of vibration of the whole set of structures in the first place. For this purpose, a commercially available FEM code was used. Three-dimensional CFD models were developed to simulate behavior of the flow when being released to the spillways, for opening values of 2, 5, 10 and 14 m, including the effect of the spillways’ deflectors. Modal analyses of the gate were performed, to take into account natural vibration frequencies in the determination of its critical velocities. After comparison of the gate’s critical velocities and velocity values from the CFD simulations, it is fair to say that the discharge flow does not directly induce vibration on the gates but rather on the spillways’ structure. This conclusion disregards flow through the gates as triggering the vibration phenomena which gave origin to this project, and puts the emphasis now on studying water flow effects on vibration in the spillway which, if not corrected on time, may ultimately lead to its catastrophic failure.

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