Recent experiments have shown that the isothermal turbulent motion of helium II is very similar to classical turbulence. This regime is characterized by a strong coupling between the superfluid vortex tangle and the normal-fluid component. To study this coupled regime we develop an approach to compute the evolution of the vortex tangle. Its key feature is that it is dynamically self-consistent, unlike previous approaches, because it takes into account the back rection of the vortex tangle onto the normal fluid. We implement this approach and study a model system which, although very idealized, gives some insight into the transfer of energy between the two fluid components.

• Received 23 February 1999

DOI:https://doi.org/10.1103/PhysRevB.60.1252