Contribution of the normal component to the thermal resistance of turbulent liquid helium

Abstract

Previous results for the velocity profile of the normal component of helium II in counterflow are used to evaluate the viscous contribution to the effective thermal resistance.\ud It turns out that such a contribution becomes considerably higher than the usual Landau estimate, because in the presence of vortices the velocity profile is appreciably different\ud from the Poiseuille parabolic profile. Thus, a marked increase of the contribution of the normal component to the thermal resistance with respect to the viscous Landau estimate\ud does not necessarily imply that the normal component is turbulent. Furthermore, we examine the influence of a possible slip flow along the walls when the radius of the tube becomes comparable to the phonon mean-free path; this implies a reduction of the thermal resistance with respect to that obtained for non-slip boundary conditions

Three-Dimensional Coupled Dynamics of the Two-Fluid Model in Superfluid He4 : Deformed Velocity Profile of Normal Fluid in Thermal Counterflow

“…The numerical studies of two-dimensional counterflow were performed [31], which differs from the 3D system. Saluto et al studied analytically the velocity profile of the normal fluid by using the one-fluid model [32,33], and found that the velocity profile could be flattened by superfluid turbulence.…”

Thermodynamics of computation and linear stability limits of superfluid refrigeration of a model computing array

“…[26] and [24] we have evaluated how much the presence of quantized vortices reduces the efficiency of the refrigeration by means of superfluid helium and in Refs. [27,28] how the profile of the heat flux (and the normal component) is modificed by their contribution. The continuity equation (2.1) has been written in terms of the specific volume V instead of the usual density ρ for future purposes.…”