Evolution of the four-vortex structure of the He II thermal counterflow based on the simplified two-fluid model

The thermal counterflow of superfluid helium past a cylinder has been found to generate two pairs of symmetrical vortexes upstream and downstream of the cylinder in experiments. This is a unique physical phenomenon that differs from classical fluids. In this paper, we have developed a new solver on the OpenFOAM (R) platform based on the simplified two-fluid model proposed by Kitamura et al. and use it to simulate the thermal counterflow phenomenon. The numerical simulation results obtained by the simplified two-fluid model agree well with the experimental results. Based on this numerical simulation, an investigation has been carried out into the evolution of the four-vortex structure of the superfluid helium thermal counterflow. This paper supports the conjecture of many researchers that large scale quantum turbulence in superfluid helium can be explained using classical mechanics. Details of the theoretical basis, the solver computational procedure, the numerical simulation results, and the discussion based on the results are presented in this paper.