THE HEAT PROPAGATION IN HELIUM WITH SUPERFLUID TURBULENCE

In the dissipative two-fluid hydrodynamics equations derived by Nemirovskii and Lebedev the comparative analysis of the terms due to superfluid turbulence is performed and their main parts are clarified as well. The set of equations for the heat propagation in helium at rest is expanded in the Mach number for the relative velocity of the component motion. The supercritical heat flow for the second sound waves is shown to be an anisotropic medium of the anomalous dispersion which does vanish for the waves propagating across the flow. The region for strong absorption of low frequency waves, which adjoins to the supercritical heat flow direction, is found. Beyond this region the sound absorption and damping are determined mainly by the steady heat flow and depend slightly upon the wave parameters. During the considecation of the propagation of step-like heat pulse in a wide channel with the initial weak turbulence the boundary problem is solved and the transient process to the steady heat flow is analyzed. The conditions for a number of experiments which allow to test the theory are presented.