Financement : ED I-MEP2
When helium-4 is cooled down near absolute zero, it reaches a superfluid state where it can flow with virtually no viscosity and possesses an extremely high thermal conductivity. Due to these properties, it is used as a refrigerant in different fields like space (satellites), medical (some MRI) and in the LHC in Geneva. Because of quantum mechanical constraints, any rotational motion of the fluid will generate quantum vortices, which possess a quantised circulation and an atom sized thickness. These vortices may reconnect with one another, changing the topology of the vortices.
When many quantum vortices interact with each other, a chaotic state may be found that resembles classical turbulence which is called by analogy quantum turbulence. In classical fluids, turbulence is associated to a random motion of the flow, where energy is transferred from large scale to small scale until the viscosity of the fluid dissipates the energy into heat. Even though the mechanism of dissipation of energy is different, significant similarities have been found at large scales between classical and quantum turbulence.
The aim of our work is to further explore the possible similarities and differences between both turbulent systems to help understand the underlying physical processes. To do so we use numerical simulation, more particularly the vortex filament model (VFM), for which new numerical methods have been implemented within our group to reduce computational times, allowing us to generate highly turbulent states well beyond what was previously possible.