Healing and relaxation in flows of helium II-I. Generalization of landau's equations

The Landau 2-fluid equations for the motion of helium II are often criticised on two grounds: they ignore healing of the wave function, and they require the superfluid percentage to change instantaneously when the thermodynamic state is altered. In 1970 Khalatnikov[4] proposed a way of incorporating relaxation effects associated with conversion between superfluid and normal fluid. Using this as our starting point and employing the techniques of modern continuum mechanics, we develop a thermodynamically acceptable generalization that incorporates both healing and relaxation phenomena. © 1977.