Dynamics of coreless vortices and rotation-induced dissipation peak in superfluid films on rotating porous substrates

Abstract

We analyze dynamics of 3D coreless vortices in superfluid films covering porous substrates. The 3D vortex dynamics is derived from the 2D dynamics of the film. The motion of a 3D vortex is a sequence of jumps between neighboring substrate cells, which can be described, nevertheless, in terms of quasi-continuous motion with average vortex velocity. The vortex velocity is derived from the dissociation rate of vortex-antivortex pairs in a 2D film, which was developed in the past on the basis of the Kosterlitz-Thouless theory. The theory explains the rotation-induced dissipation peak in torsion-oscillator experiments on 4 He films on rotating porous substrates and can be used in the analysis of other phenomena related to vortex motion in films on porous substrates.

Analysis of Vortex Motion in Porous Media

“…Depending on the completion method used in a horizontal well, fluid may enter the wellbore through perforations at various locations along the wellbore. As the distance between perforations may be insufficient to achieve a stabilized axial velocity profile, the flow pattern and the pressure gradient in a horizontal wellbore are changing along the well length [3]. Although the flow behavior in the horizontal section, with an increasing flow rate along it due to influx, and the relationship between the pressure drop and the influx from the reservoir have been recognized as one of the unsolved, yet most important problems in the production engineering, they have yet been left unqualified.…”