Transport properties of helium near the liquid-vapor critical point. V. The shear viscosity of3He-4He mixtures

Wang, S.; Meyer, Horst

doi:10.1007/bf00683328

Cited by 11 publications

(4 citation statements)

References 15 publications

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“…Both dynamic parameters w(t) and Γ(t) can be determined within the dynamical equations of model H', uncoupled to the sound degrees of freedom. We take the theoretical shear viscosity [5,6] at zero frequency and compare it with the experimental shear viscosity [21] in order to find the background values of w, f and Γ. The resulting temperature dependence of the order parameter Onsager coefficient, the mode coupling f and the parameter w is shown in figure 2b.…”

Section: Experimental Comparisonmentioning

confidence: 99%

Critical Sound in Fluids and Mixtures

Folk¹,

Moser²

1999

Condens. Matter Phys.

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The behaviour of sound is explained within the dynamical renormalization group theory. Non-asymptotic effects are due to the deviation of renormalized couplings from their fixed point values. We calculate the temperature and frequency dependence of the sound velocity and absorption near the consolute point and the gas liquid critical point in pure fluids and mixtures. The critical non-asymptotic time scale in mixtures is different from the pure fluid case and set by an effective order parameter Onsager coefficient containing the dynamical parameter related to the enhancement of the thermal conductivity. We discuss the relation to the phenomenological theory of Ferrell and Bhattacharjee for the consolute point and compare with experiments in pure 3 He, 4 He and 3 He-4 He mixtures near the plait point.

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Section: Experimental Comparisonmentioning

confidence: 99%

Critical Sound in Fluids and Mixtures

Folk¹,

Moser²

1999

Condens. Matter Phys.

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“…1 or Ref. 25). In the critical region a singularity is evident, both from a path along the coexistence curve, where r/ shows a sharp peak (truncated by gravity effects), and along the critical isochore.…”

Section: Resultsmentioning

confidence: 99%

Shear viscosity measurements of liquid 3He-4He mixtures above 0.5 K

1992

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Simultaneous measurements of (p~l) and of the molar volume are reported for liquid mixtures of 3He in 4He over the temperature range between 0.5 and 2.5 K. Here ~q is the shear viscosity and p is the mass density. In the superfluid phase, the product of the normal components, Pn and ~n, is measured. The mixtures with 3He molefractions 0.30 < X < 0.80 are studied with emphasis on the region near the superfluid transition T~ and near the phase-separation curve. Along the latter, they are compared with data by Lai and KitChens. For X > 0.5, the viscosity singularity near Tx becomes a faint peak, which however fades into the temperature-dependent background viscosity as X tends to the tricritical concentration Xt. Likewise, no singularity in 7 I is apparent when Tt is approached along the phase separation branches o-_ and or+. Furthermore, viscosity data are reported for 3He and compared with previous work. Finally, for dilute mixtures with 0.01 -< X -< 0.05, the results for 71 are compared with previous data and with predictions.

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“…Both dynamic parameters w(t) and Γ (t) can be determined within the dynamical equations of model H , uncoupled to the sound degrees of freedom. We use the theoretical shear viscosity [9] at zero frequency for a fit of the experimental shear viscosity [21] (see fig. 1 (a)).…”

mentioning

confidence: 99%

“…-Determination of the dynamical parameters for a mixture of 80%3He in4 He. From a fit (a) of the shear viscosity[21] as a function of temperature t = (T − Tc)/Tc we find the initial values for the flow of the order parameter Onsager coefficient Γ (t) (b), the mode coupling f (t) (c) and the dynamic parameter w(t) (c). We also show the effective order parameter Onsager coefficient Γ eff (t) appearing in the sound mode (see fig.2).…”

mentioning

confidence: 99%

Critical sound propagation in mixtures

Folk

Moser

1998

Europhys. Lett.

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We calculate critical effects in the sound propagation in mixtures near consolute or plait points within a non-asymptotic renormalization group theory and derive general expressions for the frequency-dependent sound velocity and sound attenuation. The critical non-asymptotic time scale in the sound mode in mixtures is set by an effective order parameter Onsager coefficient containing a dynamical parameter related to the enhancement of the thermal conductivity in the mixture, not considered so far. The differences in the critical behavior near the consolute and plait point are due to the different non-asymptotic behavior of the zero-frequency sound velocity. We compare our predictions for the sound velocity and sound absorption near the plait point in 3 He-4 He mixtures.

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Transport properties of helium near the liquid-vapor critical point. V. The shear viscosity of3He-4He mixtures

Cited by 11 publications

References 15 publications

Critical Sound in Fluids and Mixtures

Critical Sound in Fluids and Mixtures

Shear viscosity measurements of liquid 3He-4He mixtures above 0.5 K

Critical sound propagation in mixtures

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