Coupled normal fluid and superfluid profiles of turbulent helium II in channels

TL;DR

This study uses coupled two-dimensional simulations to analyze the velocity profiles of superfluid and normal fluid components in turbulent helium II channel flows, incorporating vortex back reaction and boundary effects.

Contribution

It introduces a realistic 2D model that captures vortex density distributions and reproduces experimentally observed velocity profiles in turbulent helium II flows.

Findings

Normal fluid velocity profile matches experimental observations.

Vortex density distribution aligns with 3D calculations.

Back reaction of vortices significantly influences flow profiles.

Abstract

We perform fully coupled two--dimensional numerical simulations of plane channel helium II counterflows with vortex--line density typical of experiments. The main features of our approach are the inclusion of the back reaction of the superfluid vortices on the normal fluid and the presence of solid boundaries. Despite the reduced dimensionality, our model is realistic enough to reproduce vortex density distributions across the channel recently calculated in three--dimensions. We focus on the coarse--grained superfluid and normal fluid velocity profiles, recovering the normal fluid profile recently observed employing a technique based on laser--induced fluorescence of metastable helium molecules.