THE VISCOSITY OF LIQUID HELIUM II BETWEEN 0.79° K AND THE LAMBDA POINT

1963 ◽  
Vol 41 (4) ◽  
pp. 596-609 ◽  
Author(s):  
A. D. B. Woods ◽  
A. C. Hollis Hallett
Keyword(s):  
Liquid Helium ◽  
Normal Component ◽  
Rotating Cylinder ◽  
Helium Ii ◽  
Temperature Range ◽  
Lambda Point

Values of the viscosity of the normal component of liquid helium II have been determined using the rotating cylinder (Couette type) viscometer. Primary attention has been given to the temperature range between 0.79° K and 1.1° K; values at higher temperatures have been determined to provide a check on previous determinations. The results over the whole temperature range are closely fitted by an equation of the form given by Khalatnikov (Uspekhi Fiz. Nauk, 59, 673 (1956)).

Experiments with a rotating cylinder viscometer in liquid helium II

1953 ◽  
Vol 49 (4) ◽  
pp. 717-727 ◽  
Author(s):  
A. C. Hollis-Hallett
Keyword(s):  
Liquid Helium ◽  
Normal Component ◽  
Rotating Cylinder ◽  
Mutual Friction ◽  
Rotating Fluid ◽  
Helium Ii ◽  
Lambda Point ◽  
New Type ◽  
Coefficient Of Viscosity ◽  
Cylinder Viscometer

ABSTRACTLiquid helium II was contained in the annular space between two co-axial cylinders, the inner of which was suspended by a torsion fibre while the outer was rotated at constant speeds. The torque upon the inner cylinder produced by the rotating fluid was measured for various steady velocities between 0·1 and 3 cm.sec.1, and was not found to be directly proportional to the velocity of rotation at any temperature between the lambda-point and 1·15° K. This result suggests that there must be some new type of non-linear frictional force acting in the liquid, possibly in addition to the Gorter-Mellink force of mutual friction.Extrapolation of the experimental results to zero velocity gives values of the coefficient of viscosity of the normal component which agree with the oscillating disk values between the lambda-point and about 1·6° K. At lower temperatures, the present results are significantly lower, suggesting, perhaps, that the values of the normal component density used in the analysis of the oscillating disk results were too low.

THE VISCOSITY OF LIQUID HELIUM II

1955 ◽  
Vol 33 (8) ◽  
pp. 420-435 ◽  
Author(s):  
W. J. Heikkila ◽  
A. C. Hollis Hallett
Keyword(s):  
Liquid Helium ◽  
Normal Component ◽  
Rotating Cylinder ◽  
Helium Ii ◽  
Fluid Velocities ◽  
Cylinder Viscometer

It has been found possible to use the rotating cylinder viscometer to measure the viscosity of liquid helium II between 1.13°K. and 2.18°K. provided that the fluid velocities do not exceed about 0.08 cm. sec.−1. The results, which are calculated directly from experimental observations and do not require any knowledge of the density of the normal component, can be made to fit the Landau and Khalatnikov theory for the temperatures below 1.8°K. for which the theory is applicable. The results are somewhat higher than the oscillating disk results above 1.4°K.

VISCOSITY MEASUREMENTS IN LIQUID HELIUM II

1960 ◽  
Vol 38 (10) ◽  
pp. 1376-1389 ◽  
Author(s):  
C. B. Benson ◽  
A. C. Hollis Hallett
Keyword(s):  
Liquid Helium ◽  
Significant Contribution ◽  
Normal Component ◽  
Circular Disk ◽  
Viscous Drag ◽  
Normal Fluid ◽  
Helium Ii ◽  
Torsion Suspension ◽  
Thermal Data ◽  
Cylinder Method

Measurements of the viscosity of liquid helium II have been made using an oscillating sphere. This method avoids the necessity of a "corner" correction unavoidable when a circular disk is used, and therefore eliminates the uncertainty associated with such a correction. Calibration experiments showed the presence of a significant contribution to the observed damping of the oscillations which arose from the viscous drag of the gas surrounding the rod which connected the sphere with the torsion suspension fiber. This damping has been calculated and when applied to the results obtained in liquid helium II, the values of the viscosity of the normal component which were obtained agree with those obtained by the rotating cylinder method within the combined experimental uncertainties. The assumed density of the normal fluid was that obtained from the velocity of second sound, and the most accurate thermal data available.

The absorption of sound in dilute solutions of 3 He in liquid helium II

1962 ◽  
Vol 268 (1334) ◽  
pp. 424-436 ◽  
Keyword(s):  
Liquid Helium ◽  
Sound Wave ◽  
Relaxation Times ◽  
Temperature Curve ◽  
Dilute Solutions ◽  
Helium Ii ◽  
Temperature Range ◽  
Pure Helium

The coefficient of the absorption of sound in dilute solutions of 3 He in liquid helium II has been measured in the temperature range down to 0.4 °K at a frequency of 14 Mc/s. Results are given for molar concentrations of 3 He of 0.32, 1.6 and 5.2%. In all cases the absorption is less than in pure helium II, and the peak in the absorption-temperature curve is shifted to somewhat lower temperatures. It appears that the 3 He speeds up the interactions between the thermal excitations in the liquid, and thus reduces the second viscosity which is responsible for most of the absorption in pure helium II at the higher temperatures (Khalatnikov 1950; Dransfeld, Newell & Wilks 1958). Our results are compared with a calculation of this effect due to Andreev (1961). At lower temperatures the absorption arises through a different mechanism, and a treatment taking into account the fact that all the relaxation times are long compared to the period of the sound wave has been given by Dransfeld (1958, 1962). Our results are consistent with, and give support to, Dransfeld’s treatment which involves the ‘bunching’ of the thermal phonons by the sound wave.

Superflow dissipation in liquid helium II near the lambda point

1979 ◽  
Vol 70 (4) ◽  
pp. 323-325
Author(s):  
A. Weyland ◽  
H. Geurts
Keyword(s):  
Liquid Helium ◽  
Helium Ii ◽  
Lambda Point

The absorption of sound in liquid helium II

1958 ◽  
Vol 243 (1235) ◽  
pp. 500-517 ◽  
Keyword(s):  
Liquid Helium ◽  
Thermal Transport ◽  
Kinetic Coefficient ◽  
Temperature Curve ◽  
Additional Absorption ◽  
Helium Ii ◽  
Temperature Range ◽  
Original Treatment

The absorption of sound in liquid helium II has been measured in the temperature range down to 0.4° K, at frequencies of 6.0 and 14.4 Mc, and under pressures of up to 25 atm. The results are compared with the theory of Khalatnikov (1950, 1952). Besides accounting for the existence of a maximum in the absorption-temperature curve, this theory predicts the manner in which the magnitude and position of the maximum varies with frequency, and with pressure. It is shown that these predictions are qualitatively correct, although exact numerical agreement is not obtained. The measurements also confirm the observations of Chase & Herlin (1955) that the absorption at the lower temperatures is greater than that to be expected from Khalatnikov’s original treatment. It seems that the additional absorption may arise from processes associated with the kinetic coefficient of thermal transport (Khalatnikov 1952).

Experiments with oscillating disk systems in liquid helium II

1952 ◽  
Vol 210 (1102) ◽  
pp. 404-426 ◽  
Keyword(s):  
Liquid Helium ◽  
Normal Component ◽  
Logarithmic Decrement ◽  
Navier Stokes ◽  
Disk System ◽  
Navier Stokes Equation ◽  
Helium Ii ◽  
Superfluid Component ◽  
Single Disk ◽  
Frictional Forces

An experimental study has been made of the period and logarithmic decrement of a single disk and of a pile of equally spaced disks performing torsional oscillations in liquid helium II. For small amplitudes (less than about 0.1 radian), the decay of amplitude is exponential, and from the solution of the Navier-Stokes equation deduced in the appendix, values of the viscosity were deduced from the results obtained with the single disk, and of the density of the normal component of helium n from the results from the pile of disks; the values found are in good agreement with earlier work. For larger amplitudes, the logarithmic decrement of both systems increases considerably with amplitude, and for the pile of disks the period also increases with amplitude. From the increase of period, it is concluded that the superfluid component is dragged more and more with the disk system at higher velocities, while the increase of decrement is interpreted as being due to additional frictional forces associated with the dragging of the superfluid component. The mutual frictional force proposed by Gorter & Mellink proves inadequate to explain the observed effects.

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