论文信息 - Velocity of the fourth sound in liquid helium II via extended thermodynamics

Velocity of the fourth sound in liquid helium II via extended thermodynamics

AbstractThis work continues a study begun in previous works, where, using Extended Thermodynamics, a monofluid model of liquid helium II is formulated. The wave propagation in bulk liquid helium II is studied in the hypothesis that the thermal dilatation is not zero. The propagation of fourth sound, studied previously neglecting both the thermal dilatation and finite volume of the powder, is studied without these simplified hypotheses: a scattering correction n is introduced to take into account the porosity. The model is more general than the standard two-fluid model because it allows that a small amount of entropy is associated with helium when it flows through a very thin capillary or a porous medium. A comparison with experimental data is performed. From experimental values for velocities and attenuations of the two sounds in bulk liquid helium, the model provides the velocity of fourth sound in a porous medium. These values are determined at various temperatures and pressures and compared with fourth sound measurements in a packed powder.

Maria Stella Mongiovì | M. Mongiovì | R. A. Peruzza | Rosa Anna Peruzza

[1] H. Lauter,et al. Measurement of the velocity and attenuation of fourth sound in helium II , 1979 .

[2] G. Lebon,et al. A Continuum Theory of Liquid Helium II Based on the Classical Theory of Irreversible Processes , 1979 .

[3] J. Trefny,et al. Attenuation of second sound in He II under pressure , 1976 .

[4] I. Rudnick,et al. EXPERIMENTAL DETERMINATION OF THE FOURTH SOUND VELOCITY IN HELIUM II , 1965 .

[5] K. R. Atkins. Third and Fourth Sound in Liquid Helium II , 1959 .

[6] I-Shih Liu,et al. Method of Lagrange multipliers for exploitation of the entropy principle , 1972 .

[7] Mongiovì. Extended irreversible thermodynamics of liquid helium II. , 1993, Physical review. B, Condensed matter.

[8] I-Shih Liu,et al. Extended thermodynamics of classical and degenerate ideal gases , 1983 .

[9] J. Maynard. Determination of the thermodynamics of He II from sound-velocity data , 1976 .

[10] G. Lebon,et al. Extended irreversible thermodynamics , 1993 .

[11] G. Whitham,et al. Linear and Nonlinear Waves , 1976 .

[12] I. Rudnick,et al. Precision sound-velocity measurements in He II , 1976 .

[13] I. Müller,et al. Rational Extended Thermodynamics , 1993 .